From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chris Wilson Subject: Re: [PATCH 1/2] drm/i915/intel_i2c: handle zero-length reads Date: Fri, 13 Apr 2012 13:25:33 +0100 Message-ID: <1334319941_407751@CP5-2952> References: <1334317674-32450-1-git-send-email-djkurtz@chromium.org> Return-path: In-Reply-To: <1334317674-32450-1-git-send-email-djkurtz@chromium.org> Sender: linux-kernel-owner@vger.kernel.org To: Keith Packard , David Airlie , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Daniel Vetter Cc: Daniel Kurtz List-Id: dri-devel@lists.freedesktop.org On Fri, 13 Apr 2012 19:47:53 +0800, Daniel Kurtz wrote: > A common method of probing an i2c bus is trying to do a zero-length read. > Handle this case by checking the length first waiting for data to be read. > > This is actually important, since attempting a zero-length read is one > of the ways that i2cdetect and i2c_new_probed_device detect whether > there is device present on the bus with a given address. > > Signed-off-by: Daniel Kurtz You earlier assuaged my fears that setting SW_READY without waiting would anger the hw, so Reviewed-by: Chris Wilson -Chris -- Chris Wilson, Intel Open Source Technology Centre