Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755942AbdGKRKH (ORCPT ); Tue, 11 Jul 2017 13:10:07 -0400 Received: from mail.kapsi.fi ([217.30.184.167]:53636 "EHLO mail.kapsi.fi" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755569AbdGKRKF (ORCPT ); Tue, 11 Jul 2017 13:10:05 -0400 Subject: Re: [PATCH] gpu: host1x: Free the IOMMU domain when there is no device to attach To: Paul Kocialkowski , Marcel Ziswiler , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "linux-tegra@vger.kernel.org" Cc: "jonathanh@nvidia.com" , "mperttunen@nvidia.com" , "treding@nvidia.com" , "swarren@nvidia.com" References: <20170710193305.5987-1-contact@paulk.fr> <1499762987.1340.10.camel@paulk.fr> <1499783851.1520.16.camel@toradex.com> <1499784254.1340.13.camel@paulk.fr> From: Mikko Perttunen Message-ID: <1db2411c-c1af-62f5-18b4-55523dc5b56c@kapsi.fi> Date: Tue, 11 Jul 2017 20:09:56 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.0 MIME-Version: 1.0 In-Reply-To: <1499784254.1340.13.camel@paulk.fr> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-SA-Exim-Connect-IP: 86.115.6.181 X-SA-Exim-Mail-From: cyndis@kapsi.fi X-SA-Exim-Scanned: No (on mail.kapsi.fi); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2862 Lines: 81 On 07/11/2017 05:44 PM, Paul Kocialkowski wrote: > On Tue, 2017-07-11 at 14:37 +0000, Marcel Ziswiler wrote: >> On Tue, 2017-07-11 at 11:49 +0300, Paul Kocialkowski wrote: >>> On Mon, 2017-07-10 at 21:33 +0200, Paul Kocialkowski wrote: >>>> When there is no device to attach to the IOMMU domain, as may be >>>> the >>>> case when the device-tree does not contain the proper iommu node, >>>> it >>>> is >>>> best to keep going without IOMMU support rather than failing. >>>> This allows the driver to probe and function instead of taking >>>> down >>>> all of the tegra drm driver, leading to missing display support. >>> >>> Fixes: 404bfb78daf3 ("gpu: host1x: Add IOMMU support") >>> >>>> Signed-off-by: Paul Kocialkowski >>> . >>>> org> >>>> --- >>>> drivers/gpu/host1x/dev.c | 8 +++++++- >>>> 1 file changed, 7 insertions(+), 1 deletion(-) >>>> >>>> diff --git a/drivers/gpu/host1x/dev.c b/drivers/gpu/host1x/dev.c >>>> index ac65f52850a6..f296738d0de8 100644 >>>> --- a/drivers/gpu/host1x/dev.c >>>> +++ b/drivers/gpu/host1x/dev.c >>>> @@ -186,8 +186,13 @@ static int host1x_probe(struct >>>> platform_device >>>> *pdev) >>>> return -ENOMEM; >>>> >>>> err = iommu_attach_device(host->domain, &pdev- >>>>> dev); >>>> >>>> - if (err) >>>> + if (err == -ENODEV) { >>>> + iommu_domain_free(host->domain); >>>> + host->domain = NULL; >>>> + goto iommu_skip; >>>> + } else if (err) { >>>> goto fail_free_domain; >>>> + } >>>> >>>> geometry = &host->domain->geometry; >>>> >>>> @@ -198,6 +203,7 @@ static int host1x_probe(struct platform_device >>>> *pdev) >>>> host->iova_end = geometry->aperture_end; >>>> } >>>> >>>> +iommu_skip: >>>> err = host1x_channel_list_init(host); >>>> if (err) { >>>> dev_err(&pdev->dev, "failed to initialize channel >>>> list\n"); >> >> Please note that this does no longer cleanly apply after Mikko's 'gpu: >> host1x: Refactor channel allocation code' commit from June 15 already >> applied to current -next. Other than that > > Good to know! I intended this patch for fixing 4.12 stable, so I'm not > even entirely sure it should land in next. The patch that fixes the > device-tree to actually enable the iommu should be merged in priority. > > If that is the case and anyone wants this patch rebased to next, feel > free to let me know and I'll send a rebased version. We should definitely have this for non-stable kernels too - it would be a bit strange if the driver worked if IOMMU support wasn't built into the kernel but failed if it was :) It can also be helpful for debugging to be able to disable IOMMU just for host1x. > >> Tested-by: Marcel Ziswiler >> Tested-on: Apalis TK1, Apalis T30, Beaver, Colibri T30, Jetson-TK1 >> >> Finally graphics working again, thanks guys! > > Yay! :) >