Bug 6886

Summary:	DDC for Hansol 900P sometimes fails
Product:	xorg	Reporter:	Tollef Fog Heen <tfheen>
Component:	Driver/Radeon	Assignee:	Xorg Project Team <xorg-team>
Status:	RESOLVED FIXED	QA Contact:	Xorg Project Team <xorg-team>
Severity:	normal
Priority:	high	CC:	airlied, alexdeucher
Version:	7.0 (2005.12)
Hardware:	x86 (IA32)
OS:	Linux (All)
Whiteboard:
i915 platform:		i915 features:

Description Tollef Fog Heen 2006-05-10 18:18:18 UTC

A fair amount of the time, my X server fails to detect the correct HorizSync and
VertRefresh values for my Hansol 900P (CRT).  The graphics board is a Radeon 8500.

Architecture is amd64, and it looks like it is somewhat specific to that
architecture, at least I can't remember being able to reproduce it on i386.

I discussed the problem with airlied on IRC and by his advice I ripped out the
horrendous OUTREG/INREG/usleep code in RADEONDisplayDDCConnected, but it didn't
help.

http://err.no/tmp/Xorg-640-480.log.txt is a server log where it fails,
http://err.no/tmp/xorg-works.txt is a server log where it works.

Comment 1 Alex Deucher 2006-05-13 07:30:00 UTC

Are you sure it's not the monitor?  I have an older 19" MAG which has never done
DDC reliably.

Comment 2 Tollef Fog Heen 2006-05-13 16:29:30 UTC

I seem to be utterly unable to reproduce the bug if I boot an i386 version
instead of the amd64 version I'm using, so I don't think the problem is the monitor.

Comment 3 Daniel Stone 2007-02-27 01:32:03 UTC

Sorry about the phenomenal bug spam, guys.  Adding xorg-team@ to the QA contact so bugs don't get lost in future.

Comment 4 Alex Deucher 2007-02-27 10:56:37 UTC

I suspect the i2c timeouts aren't long enough.  VESA specifies longer timeouts than standard i2c.  I'll try and add this to the radeon driver at some point.  It's a trivial patch; see the intel driver for more.

Comment 5 Alex Deucher 2007-08-31 07:35:55 UTC

does this still have problems on xserver 1.3 or newer or the latest radeon code from git?  I suspect this is related to the ddc timeouts.  my unreliable mag became very reliable after the timeouts changed.  Please re-open if you still have problems.

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