https://git.reactos.org/?p=reactos.git;a=commitdiff;h=08e9000496e4630b8f6c848df03aebfd4d74c547
commit 08e9000496e4630b8f6c848df03aebfd4d74c547 Author: Hervé Poussineau <[email protected]> AuthorDate: Sat May 29 21:37:03 2021 +0200 Commit: Hervé Poussineau <[email protected]> CommitDate: Sat Jun 5 23:38:05 2021 +0200 [VBE] Check if DDC is supported before trying to read EDID Also set Edx to 0 when reading Edid, as per specification. CORE-16695 --- win32ss/drivers/miniport/vbe/edid.c | 14 +++++++++++++- win32ss/drivers/videoprt/videoprt.c | 4 ---- 2 files changed, 13 insertions(+), 5 deletions(-) diff --git a/win32ss/drivers/miniport/vbe/edid.c b/win32ss/drivers/miniport/vbe/edid.c index a9ebe35dbbf..cde4fc35754 100644 --- a/win32ss/drivers/miniport/vbe/edid.c +++ b/win32ss/drivers/miniport/vbe/edid.c @@ -184,6 +184,19 @@ VBEReadEdid( VideoPortDebugPrint(Trace, "VBEMP: VBEReadEdid() called\n"); + /* + * Check if DDC1/DDC2 is supported + */ + VideoPortZeroMemory(&BiosRegisters, sizeof(BiosRegisters)); + BiosRegisters.Eax = VBE_DDC; + VBEDeviceExtension->Int10Interface.Int10CallBios( + VBEDeviceExtension->Int10Interface.Context, + &BiosRegisters); + if (VBE_GETRETURNCODE(BiosRegisters.Eax) != VBE_SUCCESS) + return FALSE; + if ((BiosRegisters.Ebx & 3) == 0) + return FALSE; + /* * Directly read EDID information */ @@ -191,7 +204,6 @@ VBEReadEdid( BiosRegisters.Eax = VBE_DDC; BiosRegisters.Ebx = VBE_DDC_READ_EDID; BiosRegisters.Ecx = ChildIndex; - BiosRegisters.Edx = 1; BiosRegisters.Edi = VBEDeviceExtension->TrampolineMemoryOffset; BiosRegisters.SegEs = VBEDeviceExtension->TrampolineMemorySegment; VBEDeviceExtension->Int10Interface.Int10CallBios( diff --git a/win32ss/drivers/videoprt/videoprt.c b/win32ss/drivers/videoprt/videoprt.c index 5d4c54a3559..b57cff52594 100644 --- a/win32ss/drivers/videoprt/videoprt.c +++ b/win32ss/drivers/videoprt/videoprt.c @@ -1233,10 +1233,6 @@ VideoPortEnumerateChildren( { /* Mark it invalid */ ChildExtension->EdidValid = FALSE; - // FIXME: the following break workarounds CORE-16695 - // but prevents graphic cards to return an invalid - // EDID as first child, and a valid one as second child. - break; } } }
