From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mario Kleiner Subject: Re: [PATCH 1/2] drm/i915/dp: Revert "drm/i915/dp: fall back to 18 bpp when sink capability is unknown" Date: Tue, 21 Jun 2016 17:48:50 +0200 Message-ID: <576961E2.2060005@gmail.com> References: <1464273544-23834-1-git-send-email-mario.kleiner.de@gmail.com> <1464273544-23834-2-git-send-email-mario.kleiner.de@gmail.com> <576010B3.4020904@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8"; Format="flowed" Content-Transfer-Encoding: base64 Return-path: Received: from mail-lb0-x242.google.com (mail-lb0-x242.google.com [IPv6:2a00:1450:4010:c04::242]) by gabe.freedesktop.org (Postfix) with ESMTPS id 9174E88089 for ; Tue, 21 Jun 2016 15:48:56 +0000 (UTC) Received: by mail-lb0-x242.google.com with SMTP id td3so2359044lbb.2 for ; Tue, 21 Jun 2016 08:48:56 -0700 (PDT) In-Reply-To: <576010B3.4020904@gmail.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" To: Daniel Vetter Cc: Jani Nikula , stable , dri-devel List-Id: dri-devel@lists.freedesktop.org QW55IG5ld3Mgb24gdGhpcyBvbmU/CgpUaGFua3MgYSBidW5jaCwKLW1hcmlvCgpPbiAwNi8xNC8y MDE2IDA0OjEyIFBNLCBNYXJpbyBLbGVpbmVyIHdyb3RlOgo+IE9uIDA2LzE0LzIwMTYgMDE6MDUg UE0sIERhbmllbCBWZXR0ZXIgd3JvdGU6Cj4+IE9uIFRodSwgTWF5IDI2LCAyMDE2IGF0IDQ6Mzkg UE0sIE1hcmlvIEtsZWluZXIKPj4gPG1hcmlvLmtsZWluZXIuZGVAZ21haWwuY29tPiB3cm90ZToK Pj4+IFRoaXMgcmV2ZXJ0cyBjb21taXQgMDEzZGQ5ZTAzODcyCj4+PiAoImRybS9pOTE1L2RwOiBm YWxsIGJhY2sgdG8gMTggYnBwIHdoZW4gc2luayBjYXBhYmlsaXR5IGlzIHVua25vd24iKQo+Pj4K Pj4+IFRoaXMgY29tbWl0IGludHJvZHVjZWQgYSByZWdyZXNzaW9uIGludG8gc3RhYmxlIGtlcm5l bHMsCj4+PiBhcyBpdCByZWR1Y2VzIG91dHB1dCBjb2xvciBkZXB0aCB0byA2IGJwYyBmb3IgYW55 IHZpZGVvCj4+PiBzaW5rIGNvbm5lY3RlZCB0byBhIERpc3BsYXlwb3J0IGNvbm5lY3RvciBpZiB0 aGF0IHNpbmsKPj4+IGRvZXNuJ3QgcmVwb3J0IGEgc3BlY2lmaWMgY29sb3IgZGVwdGggdmlhIEVE SUQsIG9yIGlmCj4+PiBvdXIgRURJRCBwYXJzZXIgZG9lc24ndCBhY3R1YWxseSByZWNvZ25pemUg dGhlIHByb3Blcgo+Pj4gYnBjIGZyb20gRURJRC4KPj4+Cj4+PiBBZmZlY3RlZCBhcmUgYWN0aXZl IERpc3BsYXlQb3J0LT5WR0EgY29udmVydGVycyBhbmQKPj4+IGFjdGl2ZSBEaXNwbGF5UG9ydC0+ RFZJIGNvbnZlcnRlcnMuIEJvdGggc2hvdWxkIGJlCj4+PiBhYmxlIHRvIGhhbmRsZSA4IGJwYywg YnV0IGFyZSBkZWdyYWRlZCB0byA2IGJwYyB3aXRoCj4+PiB0aGlzIHBhdGNoLgo+Pj4KPj4+IFRo ZSByZXZlcnRlZCBjb21taXQgd2FzIG1lYW50IHRvIGZpeAo+Pj4gQnVnemlsbGE6IGh0dHBzOi8v YnVnemlsbGEua2VybmVsLm9yZy9zaG93X2J1Zy5jZ2k/aWQ9MTA1MzMxCj4+Pgo+Pj4gQSBmb2xs b3d1cCBwYXRjaCBpbXBsZW1lbnRzIGEgZml4IGZvciB0aGF0IHNwZWNpZmljIGJ1ZywKPj4+IHdo aWNoIGlzIGNhdXNlZCBieSBhIGZhdWx0eSBFRElEIG9mIHRoZSBhZmZlY3RlZCBEUCBwYW5lbAo+ Pj4gYnkgYWRkaW5nIGEgbmV3IEVESUQgcXVpcmsgZm9yIHRoYXQgcGFuZWwuCj4+Pgo+Pj4gRFAg MTggYnBwIGZhbGxiYWNrIGhhbmRsaW5nIGFuZCBvdGhlciBpbXByb3ZlbWVudHMgdG8KPj4+IERQ IHNpbmsgYnBjIGRldGVjdGlvbiB3aWxsIGJlIGhhbmRsZWQgZm9yIGZ1dHVyZQo+Pj4ga2VybmVs cyBpbiBhIHNlcGFyYXRlIHNlcmllcyBvZiBwYXRjaGVzLgo+Pj4KPj4+IFBsZWFzZSBiYWNrcG9y dCB0byBzdGFibGUuCj4+Pgo+Pj4gU2lnbmVkLW9mZi1ieTogTWFyaW8gS2xlaW5lciA8bWFyaW8u a2xlaW5lci5kZUBnbWFpbC5jb20+Cj4+PiBBY2tlZC1ieTogSmFuaSBOaWt1bGEgPGphbmkubmlr dWxhQGludGVsLmNvbT4KPj4+IENjOiBzdGFibGVAdmdlci5rZXJuZWwub3JnCj4+PiBDYzogVmls bGUgU3lyasOkbMOkIDx2aWxsZS5zeXJqYWxhQGxpbnV4LmludGVsLmNvbT4KPj4+IENjOiBEYW5p ZWwgVmV0dGVyIDxkYW5pZWwudmV0dGVyQGZmd2xsLmNoPgo+Pgo+PiBJIHdvbmRlciB3aGV0aGVy IHdlIHNob3VsZG4ndCBqdXN0IG1vdmUgdGhpcyBpbnRvIHRoZSBEUCBjb2RlLCBhbmQKPj4gaW5z dGVhZCBvZiBsb29raW5nIGF0IHRoZSBlZGlkICh3aGljaCBpcyBqdXN0IHBhc3MtdGhyb3VnaCBm b3IgZHAtPnZnYQo+PiBkb25nbGVzKSB3ZSBzaG91bGQgb25seSBsb29rIGF0IGRwY2QgdmFsdWVz PyBPciBtYXliZSBvbmx5IGxvb2sgYXQgdGhlCj4+IGVkaWQgdmFsdWUgaWYgdGhlIHNpbmsgaXMg bmF0aXZlIERQLCBhbmQgbm90IHdoZW4gaXQncyBhIGRvbmdsZS4KPj4KPj4gVGhhdCB3b3VsZCBw cm9iYWJseSBhbHNvIGF2b2lkIHRoZSBxdWlyaywgYW5kIHRoYXQgcXVpcmsgc2VlbXMgYSBiaXQK Pj4gZmlzaHkuCj4+IC1EYW5pZWwKPj4KPgo+IFRoaXMgcGF0Y2ggaXMganVzdCBhIHNpbXBsZSBm aXggZm9yIHRoZSBjb2xvciBkZXB0aCByZWdyZXNzaW9uIHdoaWNoCj4gYWZmZWN0cyBzdGFibGUg a2VybmVscy4gSXQgY2FuIGJlIGJhY2stcG9ydGVkIGVhc2lseSB0byBhZmZlY3RlZCBzdGFibGUK PiBrZXJuZWxzLCBhcyBKYW5pIGFkdmlzZWQgbWUuCj4KPiBJIHdhbnRlZCB0byBjbGVhbiB1cCBh bmQgcmVzdWJtaXQgdGhhdCBEUCBoZWxwZXIgZnVuY3Rpb24gd2hpY2ggbG9va3MgYXQKPiBkcGNk IHZhbHVlcyBhbmQgbWlnaHQgYmUgYSBiaXQgdG9vIG11Y2ggZm9yIHN0YWJsZSwgb25jZSB0aGlz IGZpeCBpcyBpbi4KPgo+IC1tYXJpbwpfX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19f X19fX19fX19fX19fXwpkcmktZGV2ZWwgbWFpbGluZyBsaXN0CmRyaS1kZXZlbEBsaXN0cy5mcmVl ZGVza3RvcC5vcmcKaHR0cHM6Ly9saXN0cy5mcmVlZGVza3RvcC5vcmcvbWFpbG1hbi9saXN0aW5m by9kcmktZGV2ZWwK From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lb0-f195.google.com ([209.85.217.195]:33477 "EHLO mail-lb0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751899AbcFUPt2 (ORCPT ); Tue, 21 Jun 2016 11:49:28 -0400 Received: by mail-lb0-f195.google.com with SMTP id o4so2362434lbp.0 for ; Tue, 21 Jun 2016 08:48:55 -0700 (PDT) Subject: Re: [PATCH 1/2] drm/i915/dp: Revert "drm/i915/dp: fall back to 18 bpp when sink capability is unknown" To: Daniel Vetter References: <1464273544-23834-1-git-send-email-mario.kleiner.de@gmail.com> <1464273544-23834-2-git-send-email-mario.kleiner.de@gmail.com> <576010B3.4020904@gmail.com> Cc: dri-devel , stable , =?UTF-8?B?VmlsbGUgU3lyasOkbMOk?= , Jani Nikula From: Mario Kleiner Message-ID: <576961E2.2060005@gmail.com> Date: Tue, 21 Jun 2016 17:48:50 +0200 MIME-Version: 1.0 In-Reply-To: <576010B3.4020904@gmail.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: Any news on this one? Thanks a bunch, -mario On 06/14/2016 04:12 PM, Mario Kleiner wrote: > On 06/14/2016 01:05 PM, Daniel Vetter wrote: >> On Thu, May 26, 2016 at 4:39 PM, Mario Kleiner >> wrote: >>> This reverts commit 013dd9e03872 >>> ("drm/i915/dp: fall back to 18 bpp when sink capability is unknown") >>> >>> This commit introduced a regression into stable kernels, >>> as it reduces output color depth to 6 bpc for any video >>> sink connected to a Displayport connector if that sink >>> doesn't report a specific color depth via EDID, or if >>> our EDID parser doesn't actually recognize the proper >>> bpc from EDID. >>> >>> Affected are active DisplayPort->VGA converters and >>> active DisplayPort->DVI converters. Both should be >>> able to handle 8 bpc, but are degraded to 6 bpc with >>> this patch. >>> >>> The reverted commit was meant to fix >>> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=105331 >>> >>> A followup patch implements a fix for that specific bug, >>> which is caused by a faulty EDID of the affected DP panel >>> by adding a new EDID quirk for that panel. >>> >>> DP 18 bpp fallback handling and other improvements to >>> DP sink bpc detection will be handled for future >>> kernels in a separate series of patches. >>> >>> Please backport to stable. >>> >>> Signed-off-by: Mario Kleiner >>> Acked-by: Jani Nikula >>> Cc: stable@vger.kernel.org >>> Cc: Ville Syrjälä >>> Cc: Daniel Vetter >> >> I wonder whether we shouldn't just move this into the DP code, and >> instead of looking at the edid (which is just pass-through for dp->vga >> dongles) we should only look at dpcd values? Or maybe only look at the >> edid value if the sink is native DP, and not when it's a dongle. >> >> That would probably also avoid the quirk, and that quirk seems a bit >> fishy. >> -Daniel >> > > This patch is just a simple fix for the color depth regression which > affects stable kernels. It can be back-ported easily to affected stable > kernels, as Jani advised me. > > I wanted to clean up and resubmit that DP helper function which looks at > dpcd values and might be a bit too much for stable, once this fix is in. > > -mario