From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Vetter Subject: Re: i830 watermark problems - status? Date: Mon, 25 Nov 2013 16:23:31 +0100 Message-ID: <20131125152331.GB27344@phenom.ffwll.local> References: <1385093524-22276-1-git-send-email-keithp@keithp.com> <20131122102632.GQ27344@phenom.ffwll.local> <86d2lsem3m.fsf@miki.keithp.com> <20131122221213.GA3234@tokamak.local> <16967_1385369810_529310D2_16967_15891_1_20131125085723.GW27344@phenom.ffwll.local> <52936944.1080906@math.tu-berlin.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail-ea0-f177.google.com (mail-ea0-f177.google.com [209.85.215.177]) by gabe.freedesktop.org (Postfix) with ESMTP id B96FFFA481 for ; Mon, 25 Nov 2013 07:22:52 -0800 (PST) Received: by mail-ea0-f177.google.com with SMTP id n15so2506178ead.36 for ; Mon, 25 Nov 2013 07:22:50 -0800 (PST) Content-Disposition: inline In-Reply-To: <52936944.1080906@math.tu-berlin.de> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: intel-gfx-bounces@lists.freedesktop.org Errors-To: intel-gfx-bounces@lists.freedesktop.org To: Thomas Richter Cc: intel-gfx@lists.freedesktop.org List-Id: intel-gfx@lists.freedesktop.org On Mon, Nov 25, 2013 at 04:14:12PM +0100, Thomas Richter wrote: > Hi Daniel, hi group, > > just being curious - what is the status of the i830 watermark > problems, i.e. the state of affairs > concerning that the i830 does not allow the maximum watermark value, > but requires a "headroom" of eight entries to > avoid flickering. > > I provided a patch for this a while ago, but this seems to go > nowhere. Just to remind you: The current code does not create > a stable image on i830 based devices, even if only an internal > display is connected. > > I provided two possible attacks to the problem: A quick and dirty > method which checks for the maximum value for > i830 manually, or an overall solution which adds a "minimum" > watermark value for all supported chipsets. > > Please let me know how to proceed. I seem to be too swamped with firedrills and bugs atm to get the polished version in. The problem with just a quick hack is that we still need to switch i830M to the dual-pipe watermark function, and somehow my patch to do so seems to be broken. At least you've said that the kernel still seems to hit the single-watermark version of the function. So atm I'm a bit stalled on this :( But if you can track this down I'd go with a quick hack to enforce the minimum of 8 or so in the dual-pipe watermark function shared by gen2/3. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch