Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932092AbbLDJn1 (ORCPT ); Fri, 4 Dec 2015 04:43:27 -0500 Received: from mail9.pr.hu ([87.242.0.9]:48962 "EHLO mail9.pr.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755944AbbLDJnV (ORCPT ); Fri, 4 Dec 2015 04:43:21 -0500 Subject: Re: [PATCH v2] drm/radeon: Retry DDC probing on DVI on failure if we got an HPD interrupt To: =?UTF-8?Q?Christian_K=c3=b6nig?= , cpaul@redhat.com, Alex Deucher , David Airlie , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org References: <1449185167-6886-1-git-send-email-cpaul@redhat.com> <566154A0.5050205@amd.com> Cc: Jerome Glisse , Benjamin Tissoires From: Boszormenyi Zoltan Message-ID: <56616029.1010007@pr.hu> Date: Fri, 4 Dec 2015 10:43:05 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.3.0 MIME-Version: 1.0 In-Reply-To: <566154A0.5050205@amd.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Spam-Score: 0.6 (/) X-Scan-Signature: f863141675028d675eb61fc829984e23 X-Spam-Tracer: backend.mail.pr.hu 0.6 20151204094310Z Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1752 Lines: 40 2015-12-04 09:53 keltezéssel, Christian König írta: > On 04.12.2015 00:26, cpaul@redhat.com wrote: >> From: Lyude >> >> HPD signals on DVI ports can be fired off before the pins required for >> DDC probing actually make contact, due to the pins for HPD making >> contact first. This results in a HPD signal being asserted but DDC >> probing failing, resulting in hotplugging occasionally failing. >> >> This is somewhat rare on most cards (depending on what angle you plug >> the DVI connector in), but on some cards it happens constantly. The >> Radeon R5 on the machine used for testing this patch for instance, runs >> into this issue just about every time I try to hotplug a DVI monitor and >> as a result hotplugging almost never works. >> >> Rescheduling the hotplug work for a second when we run into an HPD >> signal with a failing DDC probe usually gives enough time for the rest >> of the connector's pins to make contact, and fixes this issue. >> >> Signed-off-by: Lyude > > I find a second a bit long, but if it works so what? > > Looks sane enough to me, patch is Reviewed-by: Christian König Does this patch help in case of the Radeon chip only has HDMI and DP outputs exposed (Zotac ZBOXNANO-AQ01) but used with DVI or VGA monitors with converter cables? We have some problems with such scenarios that sounds eerily similar to this description. Inquiry-by: Zoltán Böszörményi ;-) Thanks in advance. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/