From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ob0-f169.google.com ([209.85.214.169]:33176 "EHLO mail-ob0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753613AbcBJTey (ORCPT ); Wed, 10 Feb 2016 14:34:54 -0500 Received: by mail-ob0-f169.google.com with SMTP id is5so42633227obc.0 for ; Wed, 10 Feb 2016 11:34:53 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <56BB8338.7000504@gmail.com> References: <1454894009-15466-1-git-send-email-mario.kleiner.de@gmail.com> <1454894009-15466-6-git-send-email-mario.kleiner.de@gmail.com> <20160209100917.GP11240@phenom.ffwll.local> <56B9EF5A.6050902@gmail.com> <20160209141149.GP23290@intel.com> <20160209150347.GZ11240@phenom.ffwll.local> <56BB652A.1010107@gmail.com> <56BB8338.7000504@gmail.com> Date: Wed, 10 Feb 2016 20:34:53 +0100 Message-ID: Subject: Re: [PATCH 5/6] drm: Prevent vblank counter jumps with timestamp based update method. From: Daniel Vetter To: Mario Kleiner Cc: =?UTF-8?B?VmlsbGUgU3lyasOkbMOk?= , dri-devel , linux@bernd-steinhauser.de, stable , =?UTF-8?Q?Michel_D=C3=A4nzer?= , Vlastimil Babka , "alexander.deucher@amd.com" , =?UTF-8?Q?Christian_K=C3=B6nig?= Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: On Wed, Feb 10, 2016 at 7:36 PM, Mario Kleiner wrote: > On 02/10/2016 06:17 PM, Daniel Vetter wrote: >> >> On Wed, Feb 10, 2016 at 5:28 PM, Mario Kleiner >> wrote: >>> >>> There's another scenario where this zero-ts case can be hit. If the >>> driver >>> drm_vblank_init()'s - setting all timestamps to zero - and then code >>> starts >>> using vblanks (drm_vblank_get()) without drm_vblank_on beforehand, which >>> is >>> afaics the case with nouveau. Unless that's considered an error as well, >>> we'd need to init the timestamps to something non-zero but harmless like >>> 1 >>> usecs at drm_vblank_init() time? >> >> >> Both legacy modeset helpers and atomic ones assume by default that you >> start out with everything disabled. Pre-atomic drivers make that >> happen by calling disable_unused_functions() to shut down anything the >> bios has enabled. I think this can't happen. >> >> For drivers that do take over bootloader display config they must call >> vblank_on explicitly themselves, which i915 does. >> >>> What makes sense as output here? DRM_WARN_ONCE? >> >> >> I'd go with WARN_ON and tune it down if it's offensive. But WARN_ON >> patch for 4.6 of course. >> -Daniel >> > > Ok, so does this one have your R-b for stable as is? What about a proper > nouveau fix if i find one? Probably also for 4.6 then, given that this patch > fixes it up good enough for stable? If possible I'd prefer we just fix nouveau up for stable, and do a WARN_ON patch when this ever happens for 4.6. It sounded like you've figured out already what nouveau needs? -Daniel -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Vetter Subject: Re: [PATCH 5/6] drm: Prevent vblank counter jumps with timestamp based update method. Date: Wed, 10 Feb 2016 20:34:53 +0100 Message-ID: References: <1454894009-15466-1-git-send-email-mario.kleiner.de@gmail.com> <1454894009-15466-6-git-send-email-mario.kleiner.de@gmail.com> <20160209100917.GP11240@phenom.ffwll.local> <56B9EF5A.6050902@gmail.com> <20160209141149.GP23290@intel.com> <20160209150347.GZ11240@phenom.ffwll.local> <56BB652A.1010107@gmail.com> <56BB8338.7000504@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: Received: from mail-ob0-f180.google.com (mail-ob0-f180.google.com [209.85.214.180]) by gabe.freedesktop.org (Postfix) with ESMTPS id 300816E75F for ; Wed, 10 Feb 2016 11:34:54 -0800 (PST) Received: by mail-ob0-f180.google.com with SMTP id xk3so42676464obc.2 for ; Wed, 10 Feb 2016 11:34:54 -0800 (PST) In-Reply-To: <56BB8338.7000504@gmail.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" To: Mario Kleiner Cc: =?UTF-8?Q?Michel_D=C3=A4nzer?= , linux@bernd-steinhauser.de, stable , dri-devel , "alexander.deucher@amd.com" , =?UTF-8?Q?Christian_K=C3=B6nig?= , Vlastimil Babka List-Id: dri-devel@lists.freedesktop.org T24gV2VkLCBGZWIgMTAsIDIwMTYgYXQgNzozNiBQTSwgTWFyaW8gS2xlaW5lcgo8bWFyaW8ua2xl aW5lci5kZUBnbWFpbC5jb20+IHdyb3RlOgo+IE9uIDAyLzEwLzIwMTYgMDY6MTcgUE0sIERhbmll bCBWZXR0ZXIgd3JvdGU6Cj4+Cj4+IE9uIFdlZCwgRmViIDEwLCAyMDE2IGF0IDU6MjggUE0sIE1h cmlvIEtsZWluZXIKPj4gPG1hcmlvLmtsZWluZXIuZGVAZ21haWwuY29tPiB3cm90ZToKPj4+Cj4+ PiBUaGVyZSdzIGFub3RoZXIgc2NlbmFyaW8gd2hlcmUgdGhpcyB6ZXJvLXRzIGNhc2UgY2FuIGJl IGhpdC4gSWYgdGhlCj4+PiBkcml2ZXIKPj4+IGRybV92YmxhbmtfaW5pdCgpJ3MgLSBzZXR0aW5n IGFsbCB0aW1lc3RhbXBzIHRvIHplcm8gLSBhbmQgdGhlbiBjb2RlCj4+PiBzdGFydHMKPj4+IHVz aW5nIHZibGFua3MgKGRybV92YmxhbmtfZ2V0KCkpIHdpdGhvdXQgZHJtX3ZibGFua19vbiBiZWZv cmVoYW5kLCB3aGljaAo+Pj4gaXMKPj4+IGFmYWljcyB0aGUgY2FzZSB3aXRoIG5vdXZlYXUuIFVu bGVzcyB0aGF0J3MgY29uc2lkZXJlZCBhbiBlcnJvciBhcyB3ZWxsLAo+Pj4gd2UnZCBuZWVkIHRv IGluaXQgdGhlIHRpbWVzdGFtcHMgdG8gc29tZXRoaW5nIG5vbi16ZXJvIGJ1dCBoYXJtbGVzcyBs aWtlCj4+PiAxCj4+PiB1c2VjcyBhdCBkcm1fdmJsYW5rX2luaXQoKSB0aW1lPwo+Pgo+Pgo+PiBC b3RoIGxlZ2FjeSBtb2Rlc2V0IGhlbHBlcnMgYW5kIGF0b21pYyBvbmVzIGFzc3VtZSBieSBkZWZh dWx0IHRoYXQgeW91Cj4+IHN0YXJ0IG91dCB3aXRoIGV2ZXJ5dGhpbmcgZGlzYWJsZWQuIFByZS1h dG9taWMgZHJpdmVycyBtYWtlIHRoYXQKPj4gaGFwcGVuIGJ5IGNhbGxpbmcgZGlzYWJsZV91bnVz ZWRfZnVuY3Rpb25zKCkgdG8gc2h1dCBkb3duIGFueXRoaW5nIHRoZQo+PiBiaW9zIGhhcyBlbmFi bGVkLiBJIHRoaW5rIHRoaXMgY2FuJ3QgaGFwcGVuLgo+Pgo+PiBGb3IgZHJpdmVycyB0aGF0IGRv IHRha2Ugb3ZlciBib290bG9hZGVyIGRpc3BsYXkgY29uZmlnIHRoZXkgbXVzdCBjYWxsCj4+IHZi bGFua19vbiBleHBsaWNpdGx5IHRoZW1zZWx2ZXMsIHdoaWNoIGk5MTUgZG9lcy4KPj4KPj4+IFdo YXQgbWFrZXMgc2Vuc2UgYXMgb3V0cHV0IGhlcmU/IERSTV9XQVJOX09OQ0U/Cj4+Cj4+Cj4+IEkn ZCBnbyB3aXRoIFdBUk5fT04gYW5kIHR1bmUgaXQgZG93biBpZiBpdCdzIG9mZmVuc2l2ZS4gQnV0 IFdBUk5fT04KPj4gcGF0Y2ggZm9yIDQuNiBvZiBjb3Vyc2UuCj4+IC1EYW5pZWwKPj4KPgo+IE9r LCBzbyBkb2VzIHRoaXMgb25lIGhhdmUgeW91ciBSLWIgZm9yIHN0YWJsZSBhcyBpcz8gV2hhdCBh Ym91dCBhIHByb3Blcgo+IG5vdXZlYXUgZml4IGlmIGkgZmluZCBvbmU/IFByb2JhYmx5IGFsc28g Zm9yIDQuNiB0aGVuLCBnaXZlbiB0aGF0IHRoaXMgcGF0Y2gKPiBmaXhlcyBpdCB1cCBnb29kIGVu b3VnaCBmb3Igc3RhYmxlPwoKSWYgcG9zc2libGUgSSdkIHByZWZlciB3ZSBqdXN0IGZpeCBub3V2 ZWF1IHVwIGZvciBzdGFibGUsIGFuZCBkbyBhCldBUk5fT04gcGF0Y2ggd2hlbiB0aGlzIGV2ZXIg aGFwcGVucyBmb3IgNC42LiBJdCBzb3VuZGVkIGxpa2UgeW91J3ZlCmZpZ3VyZWQgb3V0IGFscmVh ZHkgd2hhdCBub3V2ZWF1IG5lZWRzPwotRGFuaWVsCi0tIApEYW5pZWwgVmV0dGVyClNvZnR3YXJl IEVuZ2luZWVyLCBJbnRlbCBDb3Jwb3JhdGlvbgorNDEgKDApIDc5IDM2NSA1NyA0OCAtIGh0dHA6 Ly9ibG9nLmZmd2xsLmNoCl9fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19f X19fX19fCmRyaS1kZXZlbCBtYWlsaW5nIGxpc3QKZHJpLWRldmVsQGxpc3RzLmZyZWVkZXNrdG9w Lm9yZwpodHRwczovL2xpc3RzLmZyZWVkZXNrdG9wLm9yZy9tYWlsbWFuL2xpc3RpbmZvL2RyaS1k ZXZlbAo=