Problem with xorg-server and s3c2410fb driver

Vasily Khoruzhick anarsoul at
Sat Jul 24 23:35:45 PDT 2010


I'm trying to get xorg-server + xf86-video-fbdev working on my device, and I'm 
hitting problem:

pixclock value of fb mode on my device is 260000 picosecs, and due to picosecs 
<-> khz conversions in xorg-server I'm getting rounding error:

1000000000 / 260000 = 3846
1000000000 / 3846 = 260010

(Look through xfree2fbdev_timing and fbdev2xfree_timing functions in fbdevhw.c
for more details)

xorg-server gets mode via FBOIGET_VSCREENINFO (pixclock = 260000), converts it 
to its own format, then converts it back to fbmode (due to rounding error 
pixclock - 260010) and then tries to set mode with pixvalue 260010 via 
FBIOPUT_VSCREENINFO ioctl, but driver sets it back to 260000, and xorg-server 
fails to startup with this message:

(EE) FBDEV(0): FBIOPUT_VSCREENINFO succeeded but modified mode.

With this patch:
a8/x11/server/xorg-server/files/oe/hack-fbdev-ignore-return-mode.patch xorg-
server starts with no problem, but it's ugly hack.

Is there any sane solution to fix my problem?

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