From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 49B04CCA462 for ; Fri, 16 Oct 2026 12:25:52 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 840C310E1C9; Fri, 16 Oct 2026 12:25:46 +0000 (UTC) Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by gabe.freedesktop.org (Postfix) with ESMTP id 88FE010E1C9 for ; Fri, 16 Oct 2026 12:25:40 +0000 (UTC) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id A05EB14BF for ; Fri, 16 Oct 2026 05:25:36 -0700 (PDT) Received: from [10.2.11.34] (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id A79FA3F871 for ; Fri, 16 Oct 2026 05:25:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1792153539; bh=krxKzyNI1ZYpileNc2uCsCIeFjKDXJ2c5kSdMOWJL38=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=C6/oKlqL/AOW60J29zXcLXWFT+rQU0UonsuW5Bju1JrAC7GUZ98w+ZM6+98Bn5EEf SUkBs62xkzRZ4S2dMs0b5bK0pauLm3lxuxqpz4rx5a82T5IBSQBx8qAjJlsYRjbUxA wINMfSGQsoAF7G7Hq6fURdmM/ZdylxuSbZJEEI70= Date: Fri, 16 Oct 2026 13:25:29 +0100 From: Liviu Dudau To: Boris Brezillon Cc: Steven Price , Akash Goel , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Chia-I Wu , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 0/3] drm/panthor: Misc MMU fixes/robustness improvements Message-ID: References: <20260924-panthor-mmu-fixes-v1-0-e25f9b106466@collabora.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20260924-panthor-mmu-fixes-v1-0-e25f9b106466@collabora.com> X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Thu, Sep 24, 2026 at 02:30:42PM +0200, Boris Brezillon wrote: > The first commit is fixing a bug we've seen on v13 HW. Even though > we don't quite understand what happens (race in the flush-elimination > logic when flush requests are sent concurrently from the CPU and the > MCU), it seems that the downstream driver has always been doing a > flush+invalidate of RW caches from the start, and that we were doing > so up until the atomic page table update changes, so let's go back to > that state and leave the RO L1 caches untouched. > > The second patch a fix for a race that could very well happen if we > ever end up with a failure between the as_disable() and as_enable() > calls. We've not experienced this so far, but it seems worth plugging > the hole regardless. The last patch is a much more theoretical bug, > which would involve a buggy FW telling us that a CSG is suspended, > when it's actually. I've deliberately not added a Fixes tag on the > last one for this very reason, but I think it's worth staying on > the safe side by addressing this theoretical issue, still. > > Signed-off-by: Boris Brezillon > --- > Boris Brezillon (3): > drm/panthor: Don't invalidate OTHER caches > drm/panthor: Fully disable the AS even if it's going to be re-assigned > drm/panthor: Move cache-flush after UPDATE(UNMAPPED) > > drivers/gpu/drm/panthor/panthor_mmu.c | 43 ++++++++++++++++------------------- > 1 file changed, 20 insertions(+), 23 deletions(-) > --- > base-commit: 45585c3aa285854face65293acc95eff73063d6d > change-id: 20260924-panthor-mmu-fixes-a1832dc60908 > > Best regards, > -- > Boris Brezillon > Pushed the whole series into drm-misc-next-fixes after updating the comment on 1/3 as suggested by sashiko. Best regards, Liviu -- ==================== | I would like to | | fix the world, | | but they're not | | giving me the | \ source code! / --------------- ¯\_(ツ)_/¯