Bug 12784 - radeon driver misdetects lvds dpi resulting in huge font size
Summary: radeon driver misdetects lvds dpi resulting in huge font size
Status: RESOLVED DUPLICATE of bug 10304
Alias: None
Product: xorg
Classification: Unclassified
Component: Driver/Radeon (show other bugs)
Version: git
Hardware: All All
: medium normal
Assignee: xf86-video-ati maintainers
QA Contact: Xorg Project Team
Keywords: regression
Depends on:
Reported: 2007-10-11 15:54 UTC by Chí-Thanh Christopher Nguyễn
Modified: 2007-10-11 16:41 UTC (History)
0 users

See Also:
i915 platform:
i915 features:


Description Chí-Thanh Christopher Nguyễn 2007-10-11 15:54:23 UTC
Using an Acer Aspire 5022, Mobility Radeon X700 with LVDS panel and xserver

Since upgrading from xf86-video-ati-6.7.192 to current git head, the fonts have become very large. This is because the screen size is not detected correctly. Log can be found in attachment 11987 [details].

git bisect points to this checkin:

fad9e7b00de051f632000eb2304ac23a524f7c8e is first bad commit
commit fad9e7b00de051f632000eb2304ac23a524f7c8e
Author: Alex Deucher <alex@t41p.hsd1.va.comcast.net>
Date:   Sun Sep 23 23:43:26 2007 -0400

    RADEON: Rework LVDS mode validation

    The old validation code wasn't really well suited to randr.
    This fixes several issues:
    - missing display size for panels with edid
    - broken duplicate modes

The symptoms are the same as in bug 10304. As that is also an Acer notebook, (using the intel driver instead of radeon) the cause may be related.
Comment 1 Alex Deucher 2007-10-11 16:01:32 UTC
There's nothing wrong with the driver, the edid for you panel is wrong:

Image Size:  289 x 21 mm

I'm guessing it should be 289x210mm.  Looks like we need another edid quirk.
Comment 2 Chí-Thanh Christopher Nguyễn 2007-10-11 16:36:59 UTC
Yes, the image size seems wrong. However, the panel size is 330 mm x 210 mm, which is detected correctly:

(II) RADEON(0): Max H-Image Size [cm]: horiz.: 33  vert.: 21

Also, "hwinfo --vbe" will give 

  Size: 330x210 mm

for the panel. From what I understand about EDID specifications, some smart person at Acer got confused with this
21: Maximum Horizontal Image Size (in centimeters).
22: Maximum Vertical Image Size (in centimetres).
66: Horizontal Image Size (in mm)
67: Vertical Image Size (in mm)
68: high significant bits for Horizontal Image Size (4 upper bits)
    high significant bits for Vertical Image Size (4 lower bits)
and just copied from bytes 21-22 to 66-67 (setting byte 68 to 0x10 for some reason), resulting in (256+32) mm x (0+21) mm image size for the standard timing.
Exactly the same happens in bug 10304.
Comment 3 Alex Deucher 2007-10-11 16:41:59 UTC
this is definitely a dup of bug 10304.  even your panels are the same.

*** This bug has been marked as a duplicate of bug 10304 ***

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