Re: KMS oops on 945G system

[Jesse Barnes <jbarnes@virtuousgeek.org>]

On Tue, 21 Jul 2009 22:50:31 +0200
Diego Calleja <diegocg@gmail.com> wrote:

> Hi, I'm hitting an oops when I try to enable kernel modesetting. I'm
> using one of the latests git snapshots, the one which includes some
> DRM fixes (2.6.31-rc3-00096-g78af08d-dirty). It's not a regression,
> it's the first time I try this. xserver-xorg-video-intel version is
> what was released today, 2.8.0. The problem seems to be a "division
> error" here:
> 
> (gdb) l *(intel_update_watermarks+0x5c2)
> 0x12652 is in intel_update_watermarks
> (drivers/gpu/drm/i915/intel_display.c:1881). 1876            if
> (!planea_clock || !planeb_clock) { 1877                    sr_clock =
> planea_clock ? planea_clock : planeb_clock; 1878
> line_time_us = (sr_hdisplay * 1000) / sr_clock;
> 1879                    sr_entries = (((latency_ns / line_time_us) +
> 1) * pixel_size * 1880
> sr_hdisplay) / 1000; 1881                    sr_entries =
> roundup(sr_entries / wm_params->cacheline_size, 1);
> 1882                    if (sr_entries < wm_params->fifo_size)
> 1883                            srwm = wm_params->fifo_size -
> sr_entries; 1884            }
> 
> 
> which according to git it seems to be code from this commit:
> 
> commit 7662c8bd6545c12ac7b2b39e4554c3ba34789c50
> Author: Shaohua Li <shaohua.li@intel.com>
> 
>     drm/i915: add FIFO watermark support

Yep, my bug.  Should be fixed in Eric's drm-intel-next branch:
http://git.kernel.org/?p=linux/kernel/git/anholt/drm-intel.git;a=shortlog;h=drm-intel-next

-- 
Jesse Barnes, Intel Open Source Technology Center