Em 19-04-2011 03:08, Jiri Slaby escreveu: > On 04/14/2011 12:00 AM, Russell King - ARM Linux wrote: >> On Wed, Apr 13, 2011 at 10:56:39PM +0200, Janusz Krzysztofik wrote: >>> Dnia Åroda 13 kwiecieÅ 2011 o 20:32:31 Russell King - ARM Linux >>> napisaÅ(a): >>>> On Wed, Apr 13, 2011 at 12:52:31PM +0200, Janusz Krzysztofik wrote: >>>>> Taking into account that I'm just trying to fix a regression, and >>>>> not invent a new, long term solution: are you able to name an ARM >>>>> based board which a) is already supported in 2.6.39, b) is (or can >>>>> be) equipped with a device supported by a V4L driver which uses >>>>> videobuf- dma-config susbsystem, c) has a bus structure with which >>>>> virt_to_phys(bus_to_virt(dma_handle)) is not equal dma_handle? >>>> >>>> I have no idea - and why should whether someone can name something >>>> that may break be a justification to allow something which is >>>> technically wrong? >>>> >>>> Surely it should be the other way around - if its technically wrong >>>> and _may_ break something then it shouldn't be allowed. >>> >>> In theory - of course. In practice - couldn't we now, close to -rc3, >>> relax the rules a little bit and stop bothering with something that may >>> break in the future if it doesn't break on any board supported so far (I >>> hope)? >> >> If we are worried about closeness to -final, then what should happen is >> that the original commit is reverted; the "fix" for IOMMUs resulted in >> a regression for existing users which isn't trivial to resolve without >> risking possible breakage of other users. > > Hi, as -rc4 is out, I think it's time to revert that commit and rethink > the mmap behaviour for some of next -rc1s. > > Linus, please revert > commit 35d9f510b67b10338161aba6229d4f55b4000f5b > Author: Jiri Slaby <jslaby@xxxxxxx> > Date: Mon Feb 28 06:37:02 2011 -0300 It seems the better option for now. Acked-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx> > > [media] V4L: videobuf, don't use dma addr as physical > === > > It fixes mmap when IOMMU is used on x86 only, but breaks architectures > like ARM or PPC where virt_to_phys(dma_alloc_coherent) doesn't work. We > need there dma_mmap_coherent or similar (the trickery what > snd_pcm_default_mmap does but in some saner way). But this cannot be > done at this phase. > > thanks, -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
