From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eugeni Dodonov Subject: [PATCH 1/2] drm: give up on edid retries when i2c bus is not responding Date: Thu, 5 Jan 2012 09:34:28 -0200 Message-ID: <1325763269-7245-1-git-send-email-eugeni.dodonov@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from oproxy7-pub.bluehost.com (oproxy7-pub.bluehost.com [67.222.55.9]) by gabe.freedesktop.org (Postfix) with SMTP id 52EB99E9D4 for ; Thu, 5 Jan 2012 03:33:18 -0800 (PST) List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: intel-gfx-bounces+gcfxdi-intel-gfx=m.gmane.org@lists.freedesktop.org Errors-To: intel-gfx-bounces+gcfxdi-intel-gfx=m.gmane.org@lists.freedesktop.org To: intel-gfx@lists.freedesktop.org Cc: Eugeni Dodonov List-Id: intel-gfx@lists.freedesktop.org This allows to avoid talking to a non-responding bus repeatedly until we finally timeout after 15 attempts. We can do this by catching the -ENXIO error, provided by i2c_algo_bit:bit_doAddress call. Within the bit_doAddress we already try 3 times to get the edid data, so if the routine tells us that bus is not responding, it is mostly pointless to keep re-trying those attempts over and over again until we reach final number of retries. This change should fix https://bugs.freedesktop.org/show_bug.cgi?id=41059 and improve overall edid detection timing by 10-30% in most cases, and by a much larger margin in case of phantom outputs (up to 30x in one worst case). Timing results for i915-powered machines for 'time xrandr' command: Machine 1: from 0.840s to 0.290s Machine 2: from 0.315s to 0.280s Machine 3: from +/- 4s to 0.184s Timing results for HD5770 with 'time xrandr' command: Machine 4: from 3.210s to 1.060s Reviewed-by: Chris Wilson Reviewed-by: Keith Packard Tested-by: Sean Finney Tested-by: Soren Hansen Tested-by: Hernando Torque Tested-by: Mike Lothian Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=41059 Signed-off-by: Eugeni Dodonov --- drivers/gpu/drm/drm_edid.c | 5 +++++ 1 files changed, 5 insertions(+), 0 deletions(-) diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c index 3e927ce..fb6c26c 100644 --- a/drivers/gpu/drm/drm_edid.c +++ b/drivers/gpu/drm/drm_edid.c @@ -266,6 +266,11 @@ drm_do_probe_ddc_edid(struct i2c_adapter *adapter, unsigned char *buf, } }; ret = i2c_transfer(adapter, msgs, 2); + if (ret == -ENXIO) { + DRM_DEBUG_KMS("drm: skipping non-existent adapter %s\n", + adapter->name); + break; + } } while (ret != 2 && --retries); return ret == 2 ? 0 : -1; -- 1.7.8