From: Chris Wilson <chris@chris-wilson.co.uk>
To: Intel Graphics Development <intel-gfx@lists.freedesktop.org>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>,
Daniel Kurtz <djkurtz@chromium.org>
Subject: Re: [PATCH] drm/i915: be more careful when returning -ENXIO in gmbus transfer
Date: Mon, 21 May 2012 19:24:34 +0100 [thread overview]
Message-ID: <1337624682_164153@CP5-2952> (raw)
In-Reply-To: <1337624388-32498-1-git-send-email-daniel.vetter@ffwll.ch>
On Mon, 21 May 2012 20:19:48 +0200, Daniel Vetter <daniel.vetter@ffwll.ch> wrote:
> ... flaky ddc hardware can cause a spurious NAK, resulting in the i2c
> core and drm edid functions not trying to retry the edid transfer.
>
> Luckily the gmbus quiescenting also times out for these cases, so we
> can get out of this mess by returning -ETIMEDOUT for this specific
> case. This way we keep the fast-fail of returning -ENXIO if there is
> no device present, speeding up the boot process.
>
> This regression has been introduced in
>
> commit e646d5773572bf52017983d758bdf05777dc5600
> Author: Daniel Kurtz <djkurtz@chromium.org>
> Date: Fri Mar 30 19:46:38 2012 +0800
>
> drm/i915/intel_i2c: always wait for IDLE before clearing NAK
>
> v2: Return -ETIMEDOUT for this case and keep the -ENXIO for real NAKs,
> suggested by Daniel Kurtz.
>
> Cc: Daniel Kurtz <djkurtz@chromium.org>
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=49518
> Reported-and-Tested-by: Julian Simioni <julian.simioni@gmail.com>
> Signed-Off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
-Chris
--
Chris Wilson, Intel Open Source Technology Centre
next prev parent reply other threads:[~2012-05-21 18:24 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-14 5:56 [PATCH] drm/i915: don't return -ENXIO from gmbus xfer Daniel Vetter
2012-05-19 20:10 ` Daniel Vetter
2012-05-20 15:19 ` Daniel Vetter
[not found] ` <CAGS+omCnwFf-uKiQewMnprPJ5maSjS9ROeyoRTiYd_JRBjSBiQ@mail.gmail.com>
2012-05-20 18:16 ` Daniel Vetter
2012-05-21 18:19 ` [PATCH] drm/i915: be more careful when returning -ENXIO in gmbus transfer Daniel Vetter
2012-05-21 18:24 ` Chris Wilson [this message]
[not found] ` <CAGS+omANiYtmKX_z2m2J-5j7a-K0z2MJ=wE3PcZRATmyh_VGxQ@mail.gmail.com>
2012-05-21 19:04 ` Daniel Vetter
2012-05-21 18:20 ` [PATCH] drm/i915: don't return -ENXIO from gmbus xfer Daniel Vetter
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