Re: [PATCH 1/2] drm/i915: Revert wait for vblank to prevent X refresh issues

Jesse Barnes
2010-08-24T16:39:44Z

On Tue, 24 Aug 2010 16:53:59 +0100
Sitsofe Wheeler <sitsofe@yahoo.com> wrote:

> In commit 9d0498a2bf7455159b317f19531a3e5db2ecc9c4 20ms waits were
> converted into vblank waits. One of these caused tearing, mode detection
> and redraw issues on an EeePC 900 with a more recent intel userspace (
> http://lkml.org/lkml/2010/8/23/432 ). Restoring the 20ms wait resolves
> the issue.
>
> Signed-off-by: Sitsofe Wheeler <sitsofe@yahoo.com>
> ---
> drivers/gpu/drm/i915/intel_display.c | 2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 23157e1..116d938 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -4539,7 +4539,7 @@ struct drm_crtc *intel_get_load_detect_pipe(struct intel_encoder *intel_encoder,
> encoder_funcs->commit(encoder);
> }
> /* let the connector get through one full cycle before testing */
> - intel_wait_for_vblank(dev, intel_crtc->pipe);
> + msleep(20);
>
> return crtc;
> }

Wow, tearing, mode detection and redraw problems all because of this
line? Maybe because we wait for a longer period here now? Can you
check and see if we're timing out in the wait_for_vblank function?

--
Jesse Barnes, Intel Open Source Technology Center