Fuzzy display with Intel 2.1.0 driver on LVDS

[Doug Larrick]

I am experiencing a display that is blurred in the vertical dimension
with the newly-release Intel 2.1.0 driver.  I have narrowed it down to
Git commit 1e2e301348b4168aeed38b3fdc6b0e43d5678a86, "Fix load detection
to use border region instead of blanking."

Specifically, the lines:


/*
 * Give us some border at the bottom for load detection
 */
adjusted_mode->CrtcVBlankStart = adjusted_mode->CrtcVSyncStart;
if (adjusted_mode->CrtcVBlankEnd - adjusted_mode->CrtcVBlankStart < 3)
  adjusted_mode->CrtcVBlankStart = adjusted_mode->CrtcVBlankEnd - 3;


cause me problems.  If I comment them out, my display is back to normal.
 I use a DVI-connected flat panel, through an SDVO card attached
to a 965G system.

Before this code, I have CrtcVBlankStart==1200, CrtcVSyncStart==1201,
and CrtcVBlankEnd==1250.  After this code, CrtcVBlankStart has been
moved to 1201, which I believe causes my display (Dell 2000FP LCD) to
believe there's an extra line of display and invoke its scaler.

I've attached an Xorg.log.good from a driver patched to comment out
these lines, and an Xorg.log.bad from a driver patched to print out
various values before and after these lines.  I've also attached a
simple png that can be used to demonstrate the problem by displaying it
pixel-for-pixel... it's just alternating black & white lines; when the
display is incorrect, it displays horizontal banding.  Rotate 90 degrees
and it looks normal.

Any advice for a proper fix, or better theories as to why this happens,
would be appreciated.

Thanks,
-Doug
-------------- next part --------------
A non-text attachment was scrubbed...
Name: stripes.png
Type: image/png
Size: 7139 bytes
Desc: not available
URL: <http://lists.x.org/archives/xorg/attachments/20070705/84ad7bce/attachment.png>
-------------- next part --------------
An embedded and charset-unspecified text was scrubbed...
Name: Xorg.0.log.good
URL: <http://lists.x.org/archives/xorg/attachments/20070705/84ad7bce/attachment.ksh>
-------------- next part --------------
An embedded and charset-unspecified text was scrubbed...
Name: Xorg.0.log.bad
URL: <http://lists.x.org/archives/xorg/attachments/20070705/84ad7bce/attachment-0001.ksh>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 252 bytes
Desc: OpenPGP digital signature
URL: <http://lists.x.org/archives/xorg/attachments/20070705/84ad7bce/attachment.pgp>