450 lines
14 KiB
C
450 lines
14 KiB
C
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/*++
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Copyright (c) 1990-2000 Microsoft Corporation
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Module Name:
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ddc.c
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Abstract:
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This is the NT Video port Display Data Channel (DDC) code. It contains the
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implementations for the EDID industry standard Extended Display
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Identification Data manipulations.
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Author:
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Bruce McQuistan (brucemc) 23-Sept-1996
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Environment:
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kernel mode only
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Notes:
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Based on VESA EDID Specification Version 2, April 9th, 1996
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Updated to support VESA E-DDC Proposed Standard Version 1P, July 13, 1999.
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--*/
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#include "videoprt.h"
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//
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// Make it easy to change debug verbosity.
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//
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#define DEBUG_DDC 1
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//
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// Define constants used by DDC.
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//
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#define EDID_1_SIZE 128
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#define EDID_2_SIZE 256
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#define EDID_QUERY_RETRIES 5
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#define DDC_I2C_DELAY 5 // Microseconds
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#define DDC_ADDRESS_SET_OFFSET (UCHAR)0xA0 // To set word offset into EDID
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#define DDC_ADDRESS_READ (UCHAR)0xA1 // To read EDID
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#define DDC_ADDRESS_PD_SET_OFFSET (UCHAR)0xA2 // As above for display with P&D connector
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#define DDC_ADDRESS_PD_READ (UCHAR)0xA3 // As above for display with P&D connector
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#define DDC_ADDRESS_SET_SEGMENT (UCHAR)0x60 // To set index to 256 bytes EDID segment
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#ifdef ALLOC_PRAGMA
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#pragma alloc_text (PAGE, VideoPortDDCMonitorHelper)
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#pragma alloc_text (PAGE, DDCReadEdidSegment)
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#endif // ALLOC_PRAGMA
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//
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// Exported routines.
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//
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VIDEOPORT_API
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BOOLEAN
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VideoPortDDCMonitorHelper(
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IN PVOID pHwDeviceExtension,
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IN PVOID pDDCControl,
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IN OUT PUCHAR pucEdidBuffer,
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IN ULONG ulEdidBufferSize
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)
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/*++
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Routine Description:
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This routine reads the EDID structure from the monitor using DDC.
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If caller asks for 256 bytes he may receive:
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1. One 128 bytes EDID
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2. Two 128 bytes EDIDs
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3. One 256 bytes EDID (from P&D display)
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4. No EDID
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Caller should always ask for 256 bytes, since it is impossble to
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read second 128 bytes block of the segment only.
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Arguments:
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pHwDeviceExtension - Points to per-adapter device extension.
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pDDCControl - DDC access control block.
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pucEdidBuffer - Buffer where information will be stored.
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For ACPI devices first four bytes are preset by
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the videoprt to indicated attempt to read the EDID.
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We should clear those bytes in case of the EDID
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read failure to prevent videoprt from unnecessary
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call of the ACPI method.
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ulEdidBufferSize - Size of the buffer to fill.
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Returns:
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TRUE - DDC read OK.
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FALSE - DDC read failed.
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--*/
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{
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ULONG ulChecksum; // EDID checksum
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ULONG ulScratch; // Temp variable
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ULONG ulTry; // EDID read retry counter
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ULONG ulSize; // EDID size to read
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UCHAR ucEdidSegment; // E-DDC segment to read
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BOOLEAN bEnhancedDDC; // Use enhanced DDC flag
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VIDEO_I2C_CONTROL i2CControl; // I2C lines handling functions
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PAGED_CODE();
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ASSERT(NULL != pHwDeviceExtension);
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ASSERT(NULL != pDDCControl);
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ASSERT(NULL != pucEdidBuffer);
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ASSERT(IS_HW_DEVICE_EXTENSION(pHwDeviceExtension) == TRUE);
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//
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// Check the size of the input structure.
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//
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if (((PDDC_CONTROL)pDDCControl)->Size == sizeof (I2C_FNC_TABLE))
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{
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ucEdidSegment = 0;
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bEnhancedDDC = FALSE; // Make sure we are backword compatible
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}
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else if (((PDDC_CONTROL)pDDCControl)->Size == sizeof (DDC_CONTROL))
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{
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ucEdidSegment = ((PDDC_CONTROL)pDDCControl)->EdidSegment;
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bEnhancedDDC = TRUE;
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}
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else
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{
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pVideoDebugPrint((0, "VIDEOPRT!VideoPortDDCMonitorHelper: Invalid DDC_CONTROL\n"));
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ASSERT(FALSE);
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return FALSE;
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}
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i2CControl.WriteClockLine = ((PDDC_CONTROL)pDDCControl)->I2CCallbacks.WriteClockLine;
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i2CControl.WriteDataLine = ((PDDC_CONTROL)pDDCControl)->I2CCallbacks.WriteDataLine;
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i2CControl.ReadClockLine = ((PDDC_CONTROL)pDDCControl)->I2CCallbacks.ReadClockLine;
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i2CControl.ReadDataLine = ((PDDC_CONTROL)pDDCControl)->I2CCallbacks.ReadDataLine;
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i2CControl.I2CDelay = DDC_I2C_DELAY * 10; // 100ns units
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ASSERT(NULL != i2CControl.WriteClockLine);
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ASSERT(NULL != i2CControl.WriteDataLine);
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ASSERT(NULL != i2CControl.ReadClockLine);
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ASSERT(NULL != i2CControl.ReadDataLine);
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//
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// Initialize I2C lines and switch monitor to DDC2 mode only for the first EDID.
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// This is the most time consuming operation, we don't want to repeat it.
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// We can safely assume we'll be always asked for the segment 0 first.
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// Once switched to DDC2 the monitor will stay in that mode.
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//
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if (0 == ucEdidSegment)
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{
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//
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// Initialize SDA and SCL lines to default state of released high (input).
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//
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i2CControl.WriteDataLine(pHwDeviceExtension, 1);
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DELAY_MICROSECONDS(DDC_I2C_DELAY);
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i2CControl.WriteClockLine(pHwDeviceExtension, 1);
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DELAY_MICROSECONDS(DDC_I2C_DELAY);
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//
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// Send 9 clock pulses on SCL to switch DDC2-capable monitor to DDC2 mode.
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//
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for (ulScratch = 0; ulScratch < 9; ulScratch++)
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{
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i2CControl.WriteClockLine(pHwDeviceExtension, 0);
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DELAY_MICROSECONDS(DDC_I2C_DELAY);
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i2CControl.WriteClockLine(pHwDeviceExtension, 1);
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DELAY_MICROSECONDS(DDC_I2C_DELAY);
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}
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if (I2CWaitForClockLineHigh2(pHwDeviceExtension, &i2CControl) == FALSE)
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{
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pVideoDebugPrint((0, "VIDEOPRT!VideoPortDDCMonitorHelper: Can't switch to DDC2\n"));
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RtlZeroMemory(pucEdidBuffer, sizeof (ULONG)); // Let videoprt know we tried to read
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return FALSE;
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}
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}
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//
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// Using A0/A1 we can read two 128 byte EDIDs. If we are asked for a bigger size
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// we will do two reads.
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//
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ulSize = ulEdidBufferSize > EDID_1_SIZE ? EDID_1_SIZE : ulEdidBufferSize;
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if (DDCReadEdidSegment(pHwDeviceExtension,
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&i2CControl,
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pucEdidBuffer,
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ulSize,
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ucEdidSegment,
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0x00,
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DDC_ADDRESS_SET_OFFSET,
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DDC_ADDRESS_READ,
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bEnhancedDDC) == TRUE)
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{
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if (ulEdidBufferSize <= EDID_1_SIZE)
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{
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return TRUE;
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}
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ulSize = ulEdidBufferSize - EDID_1_SIZE;
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//
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// We can read maximum two EDIDs per segment - make sure our size is correct.
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//
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if (ulSize > EDID_1_SIZE)
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{
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ulSize = EDID_1_SIZE;
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}
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//
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// We don't care about return code here - we've already got first EDID,
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// and it is possible the second one doesn't exist.
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//
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DDCReadEdidSegment(pHwDeviceExtension,
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&i2CControl,
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pucEdidBuffer + EDID_1_SIZE,
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ulSize,
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ucEdidSegment,
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0x80,
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DDC_ADDRESS_SET_OFFSET,
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DDC_ADDRESS_READ,
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bEnhancedDDC);
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return TRUE;
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}
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//
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// Check for P&D 256 EDID at A2/A3 only for segment 0.
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//
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if (0 != ucEdidSegment)
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return FALSE;
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//
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// P&D display is a special case - its 256 bytes EDID can be accessed using
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// A2/A3 or using segment 1 and A0/A1. We shoudn't read its EDID twice though
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// since we're going to use A2/A3 only if we can't read segment 0 using A0/A1,
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// which most likely means that there are no multiple EDIDs.
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//
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// Note: In this case we don't want to program E-DDC segment, so we just
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// always force bEnhancedDDC to FALSE.
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//
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return DDCReadEdidSegment(pHwDeviceExtension,
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&i2CControl,
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pucEdidBuffer,
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ulEdidBufferSize,
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ucEdidSegment,
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0x00,
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DDC_ADDRESS_PD_SET_OFFSET,
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DDC_ADDRESS_PD_READ,
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FALSE);
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} // VideoPortDDCMonitorHelper()
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//
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// Local routines.
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//
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BOOLEAN
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DDCReadEdidSegment(
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IN PVOID pHwDeviceExtension,
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IN PVIDEO_I2C_CONTROL pI2CControl,
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IN OUT PUCHAR pucEdidBuffer,
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IN ULONG ulEdidBufferSize,
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IN UCHAR ucEdidSegment,
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IN UCHAR ucEdidOffset,
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IN UCHAR ucSetOffsetAddress,
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IN UCHAR ucReadAddress,
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IN BOOLEAN bEnhancedDDC
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)
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/*++
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Routine Description:
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This routine reads the EDID structure at given segment.
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Arguments:
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pHwDeviceExtension - Points to per-adapter device extension.
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pI2CControl - I2C lines control functions.
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pucEdidBuffer - Buffer where information will be stored.
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ulEdidBufferSize - Size of the buffer to fill.
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ucEdidSegment - 256 bytes EDID segment to read.
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ucEdidOffset - Offset within the segment.
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ucSetOffsetAddress - DDC command.
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ucReadAddress - DDC command.
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bEnhancedDDC - TRUE if we want to use 0x60 for segment addressing.
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Returns:
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TRUE - DDC read OK.
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FALSE - DDC read failed.
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--*/
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{
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ULONG ulScratch; // Temp variable
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ULONG ulTry; // EDID read retry counter
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PAGED_CODE();
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ASSERT(NULL != pHwDeviceExtension);
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ASSERT(NULL != pI2CControl);
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ASSERT(NULL != pucEdidBuffer);
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ASSERT(NULL != pI2CControl->WriteClockLine);
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ASSERT(NULL != pI2CControl->WriteDataLine);
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ASSERT(NULL != pI2CControl->ReadClockLine);
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ASSERT(NULL != pI2CControl->ReadDataLine);
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ASSERT(IS_HW_DEVICE_EXTENSION(pHwDeviceExtension) == TRUE);
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for (ulTry = 0; ulTry < EDID_QUERY_RETRIES; ulTry++)
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{
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RtlZeroMemory(pucEdidBuffer, ulEdidBufferSize);
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//
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// Set EDID segment for E-DDC.
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//
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if (TRUE == bEnhancedDDC)
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{
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if (I2CStart2(pHwDeviceExtension, pI2CControl) == FALSE)
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{
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I2CStop2(pHwDeviceExtension, pI2CControl);
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pVideoDebugPrint((DEBUG_DDC, "VIDEOPRT!DDCReadEdidSegment: Failed I2C start\n"));
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continue;
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}
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pucEdidBuffer[0] = DDC_ADDRESS_SET_SEGMENT;
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pucEdidBuffer[1] = ucEdidSegment;
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if (I2CWrite2(pHwDeviceExtension, pI2CControl, pucEdidBuffer, 2) == FALSE)
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{
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//
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// For segment 0 we don't care about return code here since monitor
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// may not support E-DDC.
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//
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if (0 != ucEdidSegment)
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{
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I2CStop2(pHwDeviceExtension, pI2CControl);
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pVideoDebugPrint((DEBUG_DDC, "VIDEOPRT!DDCReadEdidSegment: Failed I2C write\n"));
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continue;
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}
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}
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}
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if (I2CStart2(pHwDeviceExtension, pI2CControl) == FALSE)
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{
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I2CStop2(pHwDeviceExtension, pI2CControl);
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pVideoDebugPrint((DEBUG_DDC, "VIDEOPRT!DDCReadEdidSegment: Failed I2C start\n"));
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continue;
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}
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//
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// Set offset to read from.
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//
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pucEdidBuffer[0] = ucSetOffsetAddress;
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pucEdidBuffer[1] = ucEdidOffset;
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if (I2CWrite2(pHwDeviceExtension, pI2CControl, pucEdidBuffer, 2) == FALSE)
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{
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I2CStop2(pHwDeviceExtension, pI2CControl);
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pVideoDebugPrint((DEBUG_DDC, "VIDEOPRT!DDCReadEdidSegment: Failed I2C write\n"));
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continue;
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}
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if (I2CStart2(pHwDeviceExtension, pI2CControl) == FALSE)
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{
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I2CStop2(pHwDeviceExtension, pI2CControl);
|
||
|
|
pVideoDebugPrint((DEBUG_DDC, "VIDEOPRT!DDCReadEdidSegment: Failed I2C start\n"));
|
||
|
|
continue;
|
||
|
|
}
|
||
|
|
|
||
|
|
//
|
||
|
|
// Tell the monitor that we want to read EDID.
|
||
|
|
//
|
||
|
|
|
||
|
|
pucEdidBuffer[0] = ucReadAddress;
|
||
|
|
|
||
|
|
if (I2CWrite2(pHwDeviceExtension, pI2CControl, pucEdidBuffer, 1) == FALSE)
|
||
|
|
{
|
||
|
|
I2CStop2(pHwDeviceExtension, pI2CControl);
|
||
|
|
pVideoDebugPrint((DEBUG_DDC, "VIDEOPRT!DDCReadEdidSegment: Failed I2C write\n"));
|
||
|
|
continue;
|
||
|
|
}
|
||
|
|
|
||
|
|
//
|
||
|
|
// Read EDID from the monitor.
|
||
|
|
//
|
||
|
|
|
||
|
|
if (I2CRead2(pHwDeviceExtension, pI2CControl, pucEdidBuffer, ulEdidBufferSize, TRUE) == FALSE)
|
||
|
|
{
|
||
|
|
I2CStop2(pHwDeviceExtension, pI2CControl);
|
||
|
|
pVideoDebugPrint((DEBUG_DDC, "VIDEOPRT!DDCReadEdidSegment: Failed I2C read\n"));
|
||
|
|
continue;
|
||
|
|
}
|
||
|
|
|
||
|
|
I2CStop2(pHwDeviceExtension, pI2CControl);
|
||
|
|
|
||
|
|
//
|
||
|
|
// Calculate the EDID checksum in case when we read full EDID.
|
||
|
|
// We should have 0x00 in LSB for proper EDID.
|
||
|
|
//
|
||
|
|
|
||
|
|
if (((EDID_1_SIZE == ulEdidBufferSize) && ((0x00 == ucEdidOffset) || (0x80 == ucEdidOffset))) ||
|
||
|
|
((EDID_2_SIZE == ulEdidBufferSize) && (0x00 == ucEdidOffset)))
|
||
|
|
{
|
||
|
|
ULONG ulChecksum = 0;
|
||
|
|
|
||
|
|
for (ulScratch = 0; ulScratch < ulEdidBufferSize; ulScratch++)
|
||
|
|
ulChecksum += pucEdidBuffer[ulScratch];
|
||
|
|
|
||
|
|
pVideoDebugPrint((DEBUG_DDC, "VIDEOPRT!DDCReadEdidSegment: EDID checksum = 0x%08X\n", ulChecksum));
|
||
|
|
|
||
|
|
if (((ulChecksum & 0xFF) == 0) &&
|
||
|
|
(0 != ulChecksum) &&
|
||
|
|
(ulChecksum != ulEdidBufferSize * 0xFF))
|
||
|
|
{
|
||
|
|
pVideoDebugPrint((DEBUG_DDC, "VIDEOPRT!DDCReadEdidSegment: Full EDID read OK\n"));
|
||
|
|
return TRUE;
|
||
|
|
}
|
||
|
|
|
||
|
|
pVideoDebugPrint((DEBUG_DDC, "VIDEOPRT!DDCReadEdidSegment: Invalid checksum\n"));
|
||
|
|
}
|
||
|
|
else
|
||
|
|
{
|
||
|
|
pVideoDebugPrint((DEBUG_DDC, "VIDEOPRT!DDCReadEdidSegment: Partial EDID read OK\n"));
|
||
|
|
return TRUE;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
pVideoDebugPrint((DEBUG_DDC, "VIDEOPRT!DDCReadEdidSegment: Failed\n"));
|
||
|
|
RtlZeroMemory(pucEdidBuffer, sizeof (ULONG)); // Let videoprt know we tried to read
|
||
|
|
return FALSE;
|
||
|
|
} // DDCReadEdidSegment()
|