[Bug 14810] New: ati driver sleeps for 1 second every 6 seconds with LCD display panel

[bugzilla-daemon at freedesktop.org]

http://bugs.freedesktop.org/show_bug.cgi?id=14810

           Summary: ati driver sleeps for 1 second every 6 seconds with LCD
                    display panel
           Product: xorg
           Version: unspecified
          Platform: x86 (IA32)
        OS/Version: Linux (All)
            Status: NEW
          Severity: normal
          Priority: medium
         Component: Driver/Radeon
        AssignedTo: xorg-driver-ati at lists.x.org
        ReportedBy: stuff at axxess.co.za
         QAContact: xorg-team at lists.x.org


I have Dell Latitude C640 with an ATI display card and a LCD display (a normal
feature for a laptop, if you ask me).  With the ATI driver for xorg that ships
with ubuntu as xserver-xorg-video-ati_6.7.195-1ubuntu2_i386.deb, I got
stop-start behaviour.  Every 6 seconds, there was a small delay.  

In my Xorg.0.log I get this every 6 seconds too:

enable montype: 2
enable montype: 2
enable montype: 2
enable montype: 2
enable montype: 2
enable montype: 2

I think it's checking whether there's a monitor plugged into the VGA port.

Here's the fix that evaporated this bug for me.  This code applies only to the
LCD display panel:

--- xserver-xorg-video-ati-6.7.195/src/radeon_display.c 2007-10-03 
01:30:52.000000000 +0200
+++ xserver-xorg-video-ati-6.7.195.patched/src/radeon_display.c 2008-02-26 
15:53:07.00000000
0 +0200
@@ -366,7 +366,6 @@
             tmp = INREG(RADEON_LVDS_GEN_CNTL);
             tmp |= (RADEON_LVDS_ON | RADEON_LVDS_BLON);
             tmp &= ~(RADEON_LVDS_DISPLAY_DIS);
-           usleep (radeon_output->PanelPwrDly * 1000);
             OUTREG(RADEON_LVDS_GEN_CNTL, tmp);
             save->lvds_gen_cntl |= (RADEON_LVDS_ON | RADEON_LVDS_BLON);
             save->lvds_gen_cntl &= ~(RADEON_LVDS_DISPLAY_DIS);


I suspect that the "usleep" was put there for a reason, but it was not
anticipated that it would get called every time the x server 
checks whether a new monitor has been attached.  (Conceivably
radeon_output->PanelPwrDly = 0 ; could work better)

Meta information:

1002:4c57 ATI Technologies Inc Radeon Mobility M7 LW [Radeon Mobility 7500]


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