Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754757AbYKKCsV (ORCPT ); Mon, 10 Nov 2008 21:48:21 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753982AbYKKCsL (ORCPT ); Mon, 10 Nov 2008 21:48:11 -0500 Received: from smtp1.linux-foundation.org ([140.211.169.13]:50976 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753765AbYKKCsK (ORCPT ); Mon, 10 Nov 2008 21:48:10 -0500 Date: Mon, 10 Nov 2008 18:47:23 -0800 (PST) From: Linus Torvalds To: Benjamin Herrenschmidt cc: Andreas Schwab , "Rafael J. Wysocki" , Linux Kernel Mailing List , Kernel Testers List , Andrew Morton , "David S. Miller" , James Cloos , Paul Collins Subject: Re: [Bug #11875] radeonfb lockup in .28-rc (bisected) In-Reply-To: <1226368174.7530.47.camel@pasglop> Message-ID: References: <1226295985.7731.7.camel@pasglop> <1226353979.7530.8.camel@pasglop> <1226360094.7530.18.camel@pasglop> <1226368174.7530.47.camel@pasglop> User-Agent: Alpine 2.00 (LFD 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1272 Lines: 29 On Tue, 11 Nov 2008, Benjamin Herrenschmidt wrote: > > In any case, I doesn't seem to be directly related to those radeonfb > changes, though a clash with X like that is indeed more likely to > actually happen if radeonfb relies more heavily on acceleration. Just a silly question, without actually looking at the code - since you now do acceleration in radeonfb, do you wait for everything to drain before you switch consoles? There could be races that depend on timing, where perhaps X is unhappy about being entered with the acceleration engine busy, or conversely the radeonfb code is unhappy about perhaps some still-in-progress X thing that hasn't been synchronously waited for.. Before, radeonfb_imageblit() would always end up doing a "radeon_engine_idle()", so in practice, I think just about any fbcon access ended up idling the engine. Now, we can probably do a lot more without syncronizing - maybe there's insufficient synchronization at the switch-over from X to text-mode or vice versa? Linus -- 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/