From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eugeni Dodonov Subject: Re: [PATCH] drm: Reduce the number of retries whilst reading EDIDs Date: Thu, 23 Feb 2012 19:36:41 -0200 Message-ID: <4F46B169.1030307@intel.com> References: <1330026771-19937-1-git-send-email-chris@chris-wilson.co.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Linus Torvalds Cc: Chris Wilson , linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, Dave Airlie , Alex Deucher List-Id: dri-devel@lists.freedesktop.org On 02/23/2012 06:15 PM, Linus Torvalds wrote: > On Thu, Feb 23, 2012 at 11:52 AM, Chris Wilson wrote: >> >> i2c retries if sees an EGAIN, drm_do_probe_ddc_edid retries until it >> gets a result and *then* drm_do_get_edid retries until it gets a result >> it is happy with. All in all, that is a lot of processor intensive >> looping in cases where we do not expect and cannot get valid data - for >> example on Intel with disconnected hardware we will busy-spin until we >> hit the i2c timeout. This is then repeated for every connector when >> querying the current status of outputs. > > Sadly, this doesn't seem to make any difference to my case. My xrandr > stays at 0.555s even with this patch. Perhaps a stupid question, but does you tree has http://cgit.freedesktop.org/~airlied/linux/commit/?h=drm-next&id=9292f37e1f5c79400254dca46f83313488093825 from Dave's drm-next? If it has, it would be the 1st time that I see xrandr take longer than .5s with that patch on an Intel GPU. We even added a check for this into intel-gpu-tools to warn us if any machine takes that long, and none had hit it so far. So if this is the case here, there is something Mac Mini-specific indeed to investigate. -Eugeni