From: Jesse Barnes <jbarnes@virtuousgeek.org>
To: Keith Packard <keithp@keithp.com>
Cc: intel-gfx@lists.freedesktop.org
Subject: Re: [PATCH 1/8] drm/i915/dp: retry link status read 3 times on failure
Date: Fri, 1 Jul 2011 16:47:00 -0700 [thread overview]
Message-ID: <20110701164700.6099691f@jbarnes-desktop> (raw)
In-Reply-To: <yund3htfu25.fsf@aiko.keithp.com>
On Fri, 01 Jul 2011 16:41:06 -0700
Keith Packard <keithp@keithp.com> wrote:
> On Fri, 1 Jul 2011 15:22:51 -0700, Jesse Barnes <jbarnes@virtuousgeek.org> wrote:
>
> > Especially after a hotplug or power status change, the sink may not
> > reply immediately to a link status query. So retry 3 times per the spec
> > to really make sure nothing is there.
>
> There's no 'false' return path here. I think you want:
> >
> > ---
> > drivers/gpu/drm/i915/intel_dp.c | 17 +++++++++++++----
> > 1 files changed, 13 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> > index 391b55f..1829ecc 100644
> > --- a/drivers/gpu/drm/i915/intel_dp.c
> > +++ b/drivers/gpu/drm/i915/intel_dp.c
> > @@ -1019,13 +1019,22 @@ intel_dp_dpms(struct drm_encoder *encoder, int mode)
> > static bool
> > intel_dp_get_link_status(struct intel_dp *intel_dp)
> > {
> > - int ret;
> > + int ret, i;
> > +
> > + /* Must try AUX reads for this at least 3 times */
> > + for (i = 0; i < 3; i++) {
> > + ret = intel_dp_aux_native_read(intel_dp,
> > + DP_LANE0_1_STATUS,
> > + intel_dp->link_status,
> > + DP_LINK_STATUS_SIZE);
> > + if (ret == DP_LINK_STATUS_SIZE)
> > + break;
>
> return true;
> > + msleep(1);
> > + }
> >
> > - ret = intel_dp_aux_native_read(intel_dp,
> > - DP_LANE0_1_STATUS,
> > - intel_dp->link_status, DP_LINK_STATUS_SIZE);
> > if (ret != DP_LINK_STATUS_SIZE)
> > return false;
I think we'd hit the "return false" above if the loop failed. But
simply returning true from the loop and false otherwise is clearer and
fewer lines. Will fix.
--
Jesse Barnes, Intel Open Source Technology Center
next prev parent reply other threads:[~2011-07-01 23:47 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-07-01 22:22 [RFC] misc DP fixes/changes Jesse Barnes
2011-07-01 22:22 ` [PATCH 1/8] drm/i915/dp: retry link status read 3 times on failure Jesse Barnes
2011-07-01 23:41 ` Keith Packard
2011-07-01 23:47 ` Jesse Barnes [this message]
2011-07-06 4:27 ` Eric Anholt
2011-07-06 16:09 ` Jesse Barnes
2011-07-01 22:22 ` [PATCH 2/8] drm/i915/dp: use DP DPCD defines when looking at DPCD values Jesse Barnes
2011-07-01 23:43 ` Keith Packard
2011-07-01 22:22 ` [PATCH 3/8] drm/i915/dp: read more receiver capability bits on hotplug Jesse Barnes
2011-07-01 23:45 ` Keith Packard
2011-07-01 22:22 ` [PATCH 4/8] drm/i915/dp: try to read receiver capabilities 3 times when detecting Jesse Barnes
2011-07-01 23:45 ` Keith Packard
2011-07-01 22:22 ` [PATCH 5/8] drm/i915/dp: set DP DPMS mode to "on" in ->commit Jesse Barnes
2011-07-01 23:46 ` Keith Packard
2011-07-01 22:22 ` [PATCH 6/8] drm/i915/dp: clear DP encoder CRTC if the receiver disappears Jesse Barnes
2011-07-01 23:48 ` Keith Packard
2011-07-01 23:59 ` Jesse Barnes
2011-07-02 0:31 ` Keith Packard
2011-07-01 22:22 ` [PATCH 7/8] drm/i915/dp: rename dpms_mode to receiver_configured Jesse Barnes
2011-07-01 23:50 ` Keith Packard
2011-07-01 22:22 ` [PATCH 8/8] drm/i915/dp: clear receiver_configured when link training fails Jesse Barnes
2011-07-01 23:51 ` Keith Packard
2011-07-01 23:39 ` [RFC] misc DP fixes/changes Keith Packard
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