From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christian Zigotzky Subject: Re: use generic DMA mapping code in powerpc V4 Date: Thu, 19 Dec 2019 14:54:27 +0100 Message-ID: References: <20181114082314.8965-1-hch@lst.de> <20181127074253.GB30186@lst.de> <87zhttfonk.fsf@concordia.ellerman.id.au> <535776df-dea3-eb26-6bf3-83f225e977df@xenosoft.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <535776df-dea3-eb26-6bf3-83f225e977df-KCoaydhb8eAb1SvskN2V4Q@public.gmane.org> Content-Language: de-DE List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Sender: "iommu" To: Michael Ellerman , Christoph Hellwig , Benjamin Herrenschmidt , Paul Mackerras Cc: linux-arch-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Darren Stevens , mad skateman , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, "contact-+1neenJGU+oAvxtiuMwx3w@public.gmane.org" , "R.T.Dickinson" , linuxppc-dev-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org List-Id: linux-arch.vger.kernel.org Hi All, We still have some issues with PCI cards in our FSL P5020 and P5040 systems since the DMA mapping updates. [1, 2] We have to limit the RAM to 3500MB for some problematic PCI cards. (kernel boot argument 'mem=3500M') The problematic DMA mapping code was added with the PowerPC updates 4.21-1 to the official kernel source code last year. [3] We have created a bug report. [4] The old 4.x kernels aren't affected because they use the old DMA code. Please check the new DMA code again. Thanks, Christian [1] http://forum.hyperion-entertainment.com/viewtopic.php?f=58&p=49486#p49486 [2] http://forum.hyperion-entertainment.com/viewtopic.php?f=58&t=4349&start=50#p49099 [3] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=8d6973327ee84c2f40dd9efd8928d4a1186c96e2 [4] https://bugzilla.kernel.org/show_bug.cgi?id=205201 On 28 November 2018 at 4:55 pm, Christian Zigotzky wrote: > On 28 November 2018 at 12:05PM, Michael Ellerman wrote: >> Nothing specific yet. >> >> I'm a bit worried it might break one of the many old obscure platforms >> we have that aren't well tested. >> > Please don't apply the new DMA mapping code if you don't be sure if it > works on all supported PowerPC machines. Is the new DMA mapping code > really necessary? It's not really nice, to rewrote code if the old > code works perfect. We must not forget, that we work for the end > users. Does the end user have advantages with this new code? Is it > faster? The old code works without any problems. I am also worried > about this code. How can I test this new DMA mapping code? > > Thanks > > From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mo4-p01-ob.smtp.rzone.de ([85.215.255.52]:36985 "EHLO mo4-p01-ob.smtp.rzone.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726760AbfLSNzL (ORCPT ); Thu, 19 Dec 2019 08:55:11 -0500 Subject: Re: use generic DMA mapping code in powerpc V4 From: Christian Zigotzky References: <20181114082314.8965-1-hch@lst.de> <20181127074253.GB30186@lst.de> <87zhttfonk.fsf@concordia.ellerman.id.au> <535776df-dea3-eb26-6bf3-83f225e977df@xenosoft.de> Message-ID: Date: Thu, 19 Dec 2019 14:54:27 +0100 MIME-Version: 1.0 In-Reply-To: <535776df-dea3-eb26-6bf3-83f225e977df@xenosoft.de> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: de-DE Sender: linux-arch-owner@vger.kernel.org List-ID: To: Michael Ellerman , Christoph Hellwig , Benjamin Herrenschmidt , Paul Mackerras Cc: linux-arch@vger.kernel.org, linux-mm@kvack.org, iommu@lists.linux-foundation.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, "R.T.Dickinson" , "contact@a-eon.com" , mad skateman , Darren Stevens Message-ID: <20191219135427.84DV5zU6taFoNSSEaK2Ov1YcBlB06JXdIRFGW_i7jxk@z> Hi All, We still have some issues with PCI cards in our FSL P5020 and P5040 systems since the DMA mapping updates. [1, 2] We have to limit the RAM to 3500MB for some problematic PCI cards. (kernel boot argument 'mem=3500M') The problematic DMA mapping code was added with the PowerPC updates 4.21-1 to the official kernel source code last year. [3] We have created a bug report. [4] The old 4.x kernels aren't affected because they use the old DMA code. Please check the new DMA code again. Thanks, Christian [1] http://forum.hyperion-entertainment.com/viewtopic.php?f=58&p=49486#p49486 [2] http://forum.hyperion-entertainment.com/viewtopic.php?f=58&t=4349&start=50#p49099 [3] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=8d6973327ee84c2f40dd9efd8928d4a1186c96e2 [4] https://bugzilla.kernel.org/show_bug.cgi?id=205201 On 28 November 2018 at 4:55 pm, Christian Zigotzky wrote: > On 28 November 2018 at 12:05PM, Michael Ellerman wrote: >> Nothing specific yet. >> >> I'm a bit worried it might break one of the many old obscure platforms >> we have that aren't well tested. >> > Please don't apply the new DMA mapping code if you don't be sure if it > works on all supported PowerPC machines. Is the new DMA mapping code > really necessary? It's not really nice, to rewrote code if the old > code works perfect. We must not forget, that we work for the end > users. Does the end user have advantages with this new code? Is it > faster? The old code works without any problems. I am also worried > about this code. How can I test this new DMA mapping code? > > Thanks > >