From: Arnd Bergmann <arnd@arndb.de> To: Ilija Hadzic <ihadzic@research.bell-labs.com> Cc: Dave Airlie <airlied@gmail.com>, Mauro Carvalho Chehab <mchehab@redhat.com>, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, Robert Morell <rmorell@nvidia.com>, sumit.semwal@linaro.org Subject: Re: [PATCH] dma-buf: Use EXPORT_SYMBOL Date: Wed, 18 Jan 2012 14:39:59 +0000 [thread overview] Message-ID: <201201181439.59338.arnd@arndb.de> (raw) In-Reply-To: <Pine.GSO.4.62.1201180733450.26200@umail> On Wednesday 18 January 2012, Ilija Hadzic wrote: > On Wed, 18 Jan 2012, Dave Airlie wrote: > > > > > The problem is the x86 nvidia binary driver does sit outside of > > subsystems, and I forsee wanting to share buffers with it from the > > Intel driver in light of the optimus hardware. Although nouveau exists > > and I'd much rather nvidia get behind that wrt the kernel stuff, I > > don't forsee that happening. > > A lot of good stuff is coming out of nvidia these days regarding for their tegra ARM socs. I wouldn't be surprised to see them in the same boat as Intel and AMD regarding their support for free drivers in the near future and I think it's worth supporting the people inside of nvidia that are fighting for that instead of the others that are against it. Having more interesting features in nouveau that are not in the proprietary driver would probably help on that front, too. > Frankly, I never understood this "low-level interface" argument that is > kicked around when EXPORT_SYMBOL_GPL topic is brought up. My view to > EXPORT_SYMBOL vs. EXPORT_SYMBOL_GPL is that it really boils down to > license controversy about binary/proprietary modules in Linux kernel. To > me it's about whether the authors of certain code (for mostly > phylosophical reasons) agree that their (GPL) code is OK or not OK to link > against non-GPL module. The controversy is about whether a module is a derived work of the kernel when you link it in. Traditionally, some modules were not considered derived works by a lot of people arguing that we have a public module interface that acts as a barrier for the license in the same way that the syscall interface lets you run proprietary applications. The EXPORT_SYMBOL_GPL is all about symbols that are too low-level to be considered part of that public module API (assuming that this API exists). The argument is that symbols which are not meant to be used in third-party modules can never be a license barrier and anything using them is a derived work even if you consider other modules not to be a derived work of the kernel. Note that this argument can still hold for low-level symbols that are marked as EXPORT_SYMBOL, using EXPORT_SYMBOL_GPL just makes it explicit. Arnd
WARNING: multiple messages have this Message-ID (diff)
From: Arnd Bergmann <arnd@arndb.de> To: Ilija Hadzic <ihadzic@research.bell-labs.com> Cc: Mauro Carvalho Chehab <mchehab@redhat.com>, Robert Morell <rmorell@nvidia.com>, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, sumit.semwal@linaro.org Subject: Re: [PATCH] dma-buf: Use EXPORT_SYMBOL Date: Wed, 18 Jan 2012 14:39:59 +0000 [thread overview] Message-ID: <201201181439.59338.arnd@arndb.de> (raw) In-Reply-To: <Pine.GSO.4.62.1201180733450.26200@umail> On Wednesday 18 January 2012, Ilija Hadzic wrote: > On Wed, 18 Jan 2012, Dave Airlie wrote: > > > > > The problem is the x86 nvidia binary driver does sit outside of > > subsystems, and I forsee wanting to share buffers with it from the > > Intel driver in light of the optimus hardware. Although nouveau exists > > and I'd much rather nvidia get behind that wrt the kernel stuff, I > > don't forsee that happening. > > A lot of good stuff is coming out of nvidia these days regarding for their tegra ARM socs. I wouldn't be surprised to see them in the same boat as Intel and AMD regarding their support for free drivers in the near future and I think it's worth supporting the people inside of nvidia that are fighting for that instead of the others that are against it. Having more interesting features in nouveau that are not in the proprietary driver would probably help on that front, too. > Frankly, I never understood this "low-level interface" argument that is > kicked around when EXPORT_SYMBOL_GPL topic is brought up. My view to > EXPORT_SYMBOL vs. EXPORT_SYMBOL_GPL is that it really boils down to > license controversy about binary/proprietary modules in Linux kernel. To > me it's about whether the authors of certain code (for mostly > phylosophical reasons) agree that their (GPL) code is OK or not OK to link > against non-GPL module. The controversy is about whether a module is a derived work of the kernel when you link it in. Traditionally, some modules were not considered derived works by a lot of people arguing that we have a public module interface that acts as a barrier for the license in the same way that the syscall interface lets you run proprietary applications. The EXPORT_SYMBOL_GPL is all about symbols that are too low-level to be considered part of that public module API (assuming that this API exists). The argument is that symbols which are not meant to be used in third-party modules can never be a license barrier and anything using them is a derived work even if you consider other modules not to be a derived work of the kernel. Note that this argument can still hold for low-level symbols that are marked as EXPORT_SYMBOL, using EXPORT_SYMBOL_GPL just makes it explicit. Arnd
next prev parent reply other threads:[~2012-01-18 14:40 UTC|newest] Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top 2012-01-06 15:06 [git pull] dma-buf tree Dave Airlie 2012-01-08 22:08 ` Linus Torvalds 2012-01-09 6:44 ` Sumit Semwal 2012-01-13 9:08 ` Dave Airlie 2012-01-13 9:38 ` Sumit Semwal 2012-01-13 9:40 ` Dave Airlie 2012-01-18 0:08 ` Expanding the use of DMA buffers in 3.3 Robert Morell 2012-01-18 0:08 ` [PATCH] dma-buf: Use EXPORT_SYMBOL Robert Morell 2012-01-18 9:10 ` Semwal, Sumit 2012-01-18 12:14 ` Arnd Bergmann 2012-01-18 12:21 ` Dave Airlie 2012-01-18 12:21 ` Dave Airlie 2012-01-18 13:55 ` Ilija Hadzic 2012-01-18 13:55 ` Ilija Hadzic 2012-01-18 14:00 ` Dave Airlie 2012-01-19 1:11 ` Robert Morell 2012-01-18 14:39 ` Arnd Bergmann [this message] 2012-01-18 14:39 ` Arnd Bergmann 2012-01-18 12:23 ` Mauro Carvalho Chehab 2012-01-19 7:26 ` Dave Airlie 2012-01-20 18:04 ` Robert Morell 2012-01-20 18:12 ` Konrad Rzeszutek Wilk 2012-01-21 17:32 ` Daniel Vetter 2012-01-25 5:34 ` Semwal, Sumit 2012-01-25 12:30 ` Alan Cox 2012-01-25 12:30 ` Alan Cox 2012-01-25 13:46 ` Mauro Carvalho Chehab 2012-01-25 13:48 ` Mauro Carvalho Chehab 2012-01-18 11:48 ` Alan Cox 2012-02-19 21:20 ` Rob Clark 2012-01-18 11:53 ` Expanding the use of DMA buffers in 3.3 Alan Cox 2012-01-18 11:53 ` Alan Cox 2012-01-19 6:43 ` Pekka Enberg 2012-01-19 6:43 ` Pekka Enberg 2012-10-10 15:56 [PATCH] dma-buf: Use EXPORT_SYMBOL Robert Morell 2012-10-10 15:56 ` Robert Morell 2012-10-10 16:23 ` Mauro Carvalho Chehab 2012-10-10 16:23 ` Mauro Carvalho Chehab 2012-10-10 18:17 ` Alan Cox 2012-10-10 21:02 ` Rob Clark 2012-10-11 6:57 ` Hans Verkuil 2012-10-11 6:57 ` Hans Verkuil 2012-10-11 11:34 ` Alan Cox 2012-10-11 11:34 ` Alan Cox 2012-10-11 11:36 ` Hans Verkuil 2012-10-11 12:10 ` Hans Verkuil 2012-10-11 12:52 ` Laurent Pinchart 2012-10-16 21:22 ` Robert Morell 2012-10-17 9:53 ` Alan Cox 2012-10-10 23:22 ` Dave Airlie 2012-10-11 1:11 ` Mauro Carvalho Chehab 2012-10-11 2:50 ` Dave Airlie 2012-10-11 11:37 ` Alan Cox 2012-10-11 7:20 ` Hans Verkuil 2012-10-11 7:51 ` Hans Verkuil 2012-10-11 9:10 ` Maarten Lankhorst 2012-10-11 11:13 ` Mauro Carvalho Chehab 2012-10-11 13:47 ` Rob Clark 2012-10-11 14:55 ` Mauro Carvalho Chehab 2012-10-11 11:30 ` Alan Cox
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