From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chris Wilson Subject: Re: [PATCH 10/13 v4] drm/i915/intel_i2c: always wait for IDLE before clearing NAK Date: Tue, 27 Mar 2012 20:17:59 +0100 Message-ID: <1332875892_117312@CP5-2952> References: <1332873382-29373-1-git-send-email-djkurtz@chromium.org> <1332873382-29373-11-git-send-email-djkurtz@chromium.org> Return-path: In-Reply-To: <1332873382-29373-11-git-send-email-djkurtz@chromium.org> Sender: linux-kernel-owner@vger.kernel.org To: Daniel Vetter , Keith Packard , David Airlie , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Cc: Benson Leung , Yufeng Shen , Daniel Kurtz List-Id: dri-devel@lists.freedesktop.org On Wed, 28 Mar 2012 02:36:19 +0800, Daniel Kurtz wrote: > The GMBUS controller can report a NAK condition while a transaction is > still active. If the driver is fast enough, and the bus is slow enough, > the driver may clear the NAK condition while the controller is still > busy, resulting in a confused GMBUS controller. This will leave the > controller in a bad state such that the next transaction may fail. > > Also, return -ENXIO if a device NAKs a transaction. > > Note: this patch also refactors gmbus_xfer to remove the "done" label. > > Signed-off-by: Daniel Kurtz Thanks for clarifying the appropriate return codes. Reviewed-by: Chris Wilson -Chris -- Chris Wilson, Intel Open Source Technology Centre