From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5D2003AB47C; Thu, 2 Jul 2026 16:28:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783009684; cv=none; b=ObqwIT40npqprexg+6NZWuThZP8GWA6DkTZGS4AaQpIN6IL3Qy+dHAgAP8ZMY/sQaeHG9FBH6bHwlScJHRzI4pkkdJCDhfb5LesJ0ZqBbgxOlzFsx5y3xb9AUu3wngTMBa+zXndRDGk11l8OXd3tE0rUALW7o6UHdRF+KkiK8es= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783009684; c=relaxed/simple; bh=YcVmSgtgk+TnUx3zgniB/pSsnMIEkZRPOTCnEI6oCEU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=psFgwhpGvfpUB4NuJyebx0n1ZvYGzTiKChJGgcME/1L+vd48TYdaMxmxvWhPjC3ZPVxLMPouNYfx6i7Zn4duupAgVDYwimaI0QoMH1kTSXD3dRNknBG9NO4LpYntskN/foJW5XSLfsvsk9Q5ldjxf9HSaai+bFzU13UnUm14nCU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=B2QZ50gr; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="B2QZ50gr" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 14B411F00A3D; Thu, 2 Jul 2026 16:27:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1783009680; bh=1U+FLJJA6qYFutBHtntvZwmWKDu2vuEHPGgH1mBN7Pg=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=B2QZ50gr2JQPHZKokpfUU9LHrrccS/KYIZs+/dSrNklT958BgF39XY1TzkYNgPxCy U4rcWlfV1giOiP0Pv2C2pKsRIiVL3mDvam+bmAU2Vm8b8E41YGQFim9bpbRI3u/ooC lunFP7xaRfIa97A5Zlf23mlu93BtuEiO49e6vyuc= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jose Maria Casanova Crespo , Iago Toral Quiroga , =?UTF-8?q?Ma=C3=ADra=20Canal?= , Sasha Levin Subject: [PATCH 5.15 09/95] drm/v3d: Skip CSD when it has zeroed workgroups Date: Thu, 2 Jul 2026 18:19:12 +0200 Message-ID: <20260702155109.404421983@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260702155109.196223802@linuxfoundation.org> References: <20260702155109.196223802@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Maíra Canal [ Upstream commit 7f93fad5ea0affc9e1505dd0f7596c0fdb496213 ] A compute shader dispatch encodes its workgroup counts in the CFG0..CFG2 registers. Kicking off a dispatch with a zero count in any of the three dimensions is invalid. First, the hardware will process 0 as 65536, while the user-space driver exposes a maximum of 65535. Over that, a submission with a zeroed workgroup dimension should be a no-op. These zeroed counts can reach the dispatch path through an indirect CSD job, whose workgroup counts are only known once the indirect buffer is read and may legitimately be zero, but such scenario should only result in a no-op. Overwrite the indirect CSD job workgroup counts with the indirect BO ones, even if they are zeroed, and don't submit the job to the hardware when any of the workgroup counts is zero, so the job completes immediately instead of running the shader. Cc: stable@vger.kernel.org Fixes: d223f98f0209 ("drm/v3d: Add support for compute shader dispatch.") Suggested-by: Jose Maria Casanova Crespo Reviewed-by: Iago Toral Quiroga Link: https://patch.msgid.link/20260602-v3d-fix-indirect-csd-v4-2-654309e32bc0@igalia.com Signed-off-by: Maíra Canal Signed-off-by: Sasha Levin --- drivers/gpu/drm/v3d/v3d_sched.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/drivers/gpu/drm/v3d/v3d_sched.c b/drivers/gpu/drm/v3d/v3d_sched.c index db98855741ee85..46c52d89cb2498 100644 --- a/drivers/gpu/drm/v3d/v3d_sched.c +++ b/drivers/gpu/drm/v3d/v3d_sched.c @@ -257,6 +257,16 @@ v3d_csd_job_run(struct drm_sched_job *sched_job) return NULL; } + /* The HW interprets a workgroup size of 0 as 65536; however, the + * user-space driver exposes a maximum of 65535. Therefore, a 0 in + * any dimension means that we have no workgroups and the compute + * shader should not be dispatched. + */ + if (!V3D_GET_FIELD(job->args.cfg[0], V3D_CSD_QUEUED_CFG0_NUM_WGS_X) || + !V3D_GET_FIELD(job->args.cfg[1], V3D_CSD_QUEUED_CFG1_NUM_WGS_Y) || + !V3D_GET_FIELD(job->args.cfg[2], V3D_CSD_QUEUED_CFG2_NUM_WGS_Z)) + return NULL; + v3d->queue[V3D_CSD].active_job = &job->base; v3d_invalidate_caches(v3d); -- 2.53.0