BUG: kworker hangs the GPU on drm and i915 since 3.8.x under X11

[Daniel Vetter]

On Sat, Apr 6, 2013 at 12:01 AM, George Amanakis <g_amanakis at yahoo.com> wrote:
> I mean that I can type, move the mouse pointer, open new windows but there
> is a lag until these changes are displayed. Stuttering like.
>
> I ended up not reverting the aforementioned commit but modifying it. This
> also solves the issue. Here is the patch:

Indeed, the commit you've bisected too accidentally removed this
check. I'll submit a patch.So I guess you've explicitly set
drm_kms_helper.poll=0. Can you please elaborate what you're working
around with this option? Any such case is a bug.

Also, can you please test latest 3.9-rc kernels (without your patch,
i.e. a broken configuration)? It contains some rework to make hpd
detection less intrusive for normal desktop activity and should also
greatly help for your case here.

Thanks, Daniel


>
> diff -rupN a/drivers/gpu/drm/drm_crtc_helper.c
> b/drivers/gpu/drm/drm_crtc_helper.c
> --- a/drivers/gpu/drm/drm_crtc_helper.c    2013-02-19 00:58:34.000000000
> +0100
> +++ b/drivers/gpu/drm/drm_crtc_helper.c    2013-04-05 23:10:36.454936677
> +0200
> @@ -1067,7 +1067,7 @@ void drm_helper_hpd_irq_event(struct drm
>      enum drm_connector_status old_status;
>      bool changed = false;
>
> -    if (!dev->mode_config.poll_enabled)
> +    if (!dev->mode_config.poll_enabled || !drm_kms_helper_poll)
>          return;
>
>      mutex_lock(&dev->mode_config.mutex);
>



--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch