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Groups > linux.kernel > #1682394
| From | Arnd Bergmann <arnd@arndb.de> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [RFC PATCH 1/5] base: dma-mapping: Export commonly used symbols |
| Date | 2017-07-06 14:30 +0200 |
| Message-ID | <u0e4X-4gf-43@gated-at.bofh.it> (permalink) |
| References | (4 earlier) <tZWhJ-MR-35@gated-at.bofh.it> <u045A-5Wp-27@gated-at.bofh.it> <u0akI-1Ps-39@gated-at.bofh.it> <u0aun-1Sl-33@gated-at.bofh.it> <u0aE2-1W0-15@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Thu, Jul 6, 2017 at 10:36 AM, Tomasz Figa <tfiga@chromium.org> wrote:
> On Thu, Jul 6, 2017 at 5:34 PM, Tomasz Figa <tfiga@chromium.org> wrote:
>> On Thu, Jul 6, 2017 at 5:26 PM, Arnd Bergmann <arnd@arndb.de> wrote:
>>> On Thu, Jul 6, 2017 at 3:44 AM, Tomasz Figa <tfiga@chromium.org> wrote:
>>
>> I'd say that this is something that has been consistently tried to be
>> avoided by V4L2 and that's why it's so tightly integrated with DMA
>> mapping. IMHO re-implementing the code that's already there in
>> videobuf2 again in the driver, only because, for no good reason
>> mentioned as for now, having a loadable module providing DMA ops was
>> disliked.
>
> Sorry, I intended to mean:
>
> IMHO re-implementing the code that's already there in videobuf2 again
> in the driver, only because, for no good reason mentioned as for now,
> having a loadable module providing DMA ops was disliked, would make no
> sense.
Why would we need to duplicate that code? I would expect that the videobuf2
core can simply call the regular dma_mapping interfaces, and you handle the
IOPTE generation at the point when the buffer is handed off from the core
code to the device driver. Am I missing something?
Arnd
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[RFC PATCH 0/5] Fixes for loadable modules implementing DMA/IOMMU APIs Tomasz Figa <tfiga@chromium.org> - 2017-07-05 09:20 +0200
[RFC PATCH 5/5] iommu/dma: Add iommu_dma_cleanup() Tomasz Figa <tfiga@chromium.org> - 2017-07-05 09:20 +0200
[RFC PATCH 2/5] base: dma-mapping: Provide a function to look up remapped pages Tomasz Figa <tfiga@chromium.org> - 2017-07-05 09:20 +0200
[RFC PATCH 3/5] iommu: Export non-static functions to use in modules Tomasz Figa <tfiga@chromium.org> - 2017-07-05 09:20 +0200
[RFC PATCH 1/5] base: dma-mapping: Export commonly used symbols Tomasz Figa <tfiga@chromium.org> - 2017-07-05 09:20 +0200
Re: [RFC PATCH 1/5] base: dma-mapping: Export commonly used symbols Christoph Hellwig <hch@lst.de> - 2017-07-05 17:20 +0200
Re: [RFC PATCH 1/5] base: dma-mapping: Export commonly used symbols Tomasz Figa <tfiga@chromium.org> - 2017-07-05 17:30 +0200
Re: [RFC PATCH 1/5] base: dma-mapping: Export commonly used symbols Christoph Hellwig <hch@lst.de> - 2017-07-05 19:30 +0200
Re: [RFC PATCH 1/5] base: dma-mapping: Export commonly used symbols Tomasz Figa <tfiga@chromium.org> - 2017-07-06 03:50 +0200
Re: [RFC PATCH 1/5] base: dma-mapping: Export commonly used symbols Arnd Bergmann <arnd@arndb.de> - 2017-07-06 10:30 +0200
Re: [RFC PATCH 1/5] base: dma-mapping: Export commonly used symbols Tomasz Figa <tfiga@chromium.org> - 2017-07-06 10:40 +0200
Re: [RFC PATCH 1/5] base: dma-mapping: Export commonly used symbols Tomasz Figa <tfiga@chromium.org> - 2017-07-06 10:50 +0200
Re: [RFC PATCH 1/5] base: dma-mapping: Export commonly used symbols Arnd Bergmann <arnd@arndb.de> - 2017-07-06 14:30 +0200
Re: [RFC PATCH 1/5] base: dma-mapping: Export commonly used symbols Tomasz Figa <tfiga@chromium.org> - 2017-07-06 15:40 +0200
Re: [RFC PATCH 1/5] base: dma-mapping: Export commonly used symbols Tomasz Figa <tfiga@chromium.org> - 2017-07-06 15:50 +0200
Re: [RFC PATCH 1/5] base: dma-mapping: Export commonly used symbols Tomasz Figa <tfiga@chromium.org> - 2017-07-06 16:10 +0200
Re: [RFC PATCH 1/5] base: dma-mapping: Export commonly used symbols Arnd Bergmann <arnd@arndb.de> - 2017-07-06 16:30 +0200
Re: [RFC PATCH 1/5] base: dma-mapping: Export commonly used symbols Tomasz Figa <tfiga@chromium.org> - 2017-07-06 16:40 +0200
Re: [RFC PATCH 1/5] base: dma-mapping: Export commonly used symbols Arnd Bergmann <arnd@arndb.de> - 2017-07-06 16:10 +0200
Re: [RFC PATCH 1/5] base: dma-mapping: Export commonly used symbols Arnd Bergmann <arnd@arndb.de> - 2017-07-06 16:00 +0200
[RFC PATCH 4/5] iommu/dma: Export non-static functions to use in modules Tomasz Figa <tfiga@chromium.org> - 2017-07-05 09:20 +0200
Re: [RFC PATCH 4/5] iommu/dma: Export non-static functions to use in modules Robin Murphy <robin.murphy@arm.com> - 2017-07-05 18:30 +0200
Re: [RFC PATCH 4/5] iommu/dma: Export non-static functions to use in modules Tomasz Figa <tfiga@chromium.org> - 2017-07-06 04:30 +0200
Re: [RFC PATCH 4/5] iommu/dma: Export non-static functions to use in modules Robin Murphy <robin.murphy@arm.com> - 2017-07-06 13:20 +0200
Re: [RFC PATCH 4/5] iommu/dma: Export non-static functions to use in modules Christoph Hellwig <hch@lst.de> - 2017-07-06 16:20 +0200
Re: [RFC PATCH 4/5] iommu/dma: Export non-static functions to use in modules Tomasz Figa <tfiga@chromium.org> - 2017-07-06 16:20 +0200
Re: [RFC PATCH 4/5] iommu/dma: Export non-static functions to use in modules Tomasz Figa <tfiga@chromium.org> - 2017-07-06 16:30 +0200
Re: [RFC PATCH 4/5] iommu/dma: Export non-static functions to use in modules Arnd Bergmann <arnd@arndb.de> - 2017-07-06 16:40 +0200
Re: [RFC PATCH 4/5] iommu/dma: Export non-static functions to use in modules Tomasz Figa <tfiga@chromium.org> - 2017-07-06 16:50 +0200
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