Re: [Linaro-mm-sig] [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-06-03 Thread Sumit Semwal
On 3 June 2015 at 15:07, Hans Verkuil wrote: > On 06/03/15 10:41, Russell King - ARM Linux wrote: >> On Wed, Jun 03, 2015 at 08:39:55AM +0200, Hans Verkuil wrote: >>> Hi Sumit, >>> >>> On 05/05/2015 04:41 PM, Sumit Semwal wrote: Hi Russell, everyone, First up, sincere apologies for

Re: [Linaro-mm-sig] [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-06-03 Thread Hans Verkuil
On 06/03/15 10:41, Russell King - ARM Linux wrote: > On Wed, Jun 03, 2015 at 08:39:55AM +0200, Hans Verkuil wrote: >> Hi Sumit, >> >> On 05/05/2015 04:41 PM, Sumit Semwal wrote: >>> Hi Russell, everyone, >>> >>> First up, sincere apologies for being awol for sometime; had some >>> personal / medica

Re: [Linaro-mm-sig] [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-06-03 Thread Russell King - ARM Linux
On Wed, Jun 03, 2015 at 08:39:55AM +0200, Hans Verkuil wrote: > Hi Sumit, > > On 05/05/2015 04:41 PM, Sumit Semwal wrote: > > Hi Russell, everyone, > > > > First up, sincere apologies for being awol for sometime; had some > > personal / medical things to take care of, and then I thought I'd wait

Re: [Linaro-mm-sig] [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-06-02 Thread Hans Verkuil
Hi Sumit, On 05/05/2015 04:41 PM, Sumit Semwal wrote: > Hi Russell, everyone, > > First up, sincere apologies for being awol for sometime; had some > personal / medical things to take care of, and then I thought I'd wait > for the merge window to get over before beginning to discuss this > again.

Re: [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-05-05 Thread Sumit Semwal
Hi Russell, everyone, First up, sincere apologies for being awol for sometime; had some personal / medical things to take care of, and then I thought I'd wait for the merge window to get over before beginning to discuss this again. On 11 February 2015 at 21:53, Russell King - ARM Linux wrote: >

Re: [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-02-11 Thread Russell King - ARM Linux
On Wed, Feb 11, 2015 at 01:20:24PM +0100, Marek Szyprowski wrote: > Hello, > > On 2015-02-11 12:12, Russell King - ARM Linux wrote: > >Which is a damn good reason to NAK it - by that admission, it's a half-baked > >idea. > > > >If all we want to know is whether the importer can accept only contigu

Re: [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-02-11 Thread Rob Clark
On Wed, Feb 11, 2015 at 7:56 AM, Daniel Vetter wrote: > On Wed, Feb 11, 2015 at 06:23:52AM -0500, Rob Clark wrote: >> On Wed, Feb 11, 2015 at 6:12 AM, Russell King - ARM Linux >> wrote: >> > As I've already pointed out, there's a major problem if you have already >> > had a less restrictive attac

Re: [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-02-11 Thread Daniel Vetter
On Wed, Feb 11, 2015 at 06:23:52AM -0500, Rob Clark wrote: > On Wed, Feb 11, 2015 at 6:12 AM, Russell King - ARM Linux > wrote: > > As I've already pointed out, there's a major problem if you have already > > had a less restrictive attachment which has an active mapping, and a new > > more restric

Re: [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-02-11 Thread Marek Szyprowski
Hello, On 2015-02-11 12:12, Russell King - ARM Linux wrote: On Wed, Feb 11, 2015 at 09:28:37AM +0100, Marek Szyprowski wrote: On 2015-01-27 09:25, Sumit Semwal wrote: Add some helpers to share the constraints of devices while attaching to the dmabuf buffer. At each attach, the constraints are

Re: [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-02-11 Thread Rob Clark
On Wed, Feb 11, 2015 at 6:12 AM, Russell King - ARM Linux wrote: > On Wed, Feb 11, 2015 at 09:28:37AM +0100, Marek Szyprowski wrote: >> Hello, >> >> On 2015-01-27 09:25, Sumit Semwal wrote: >> >Add some helpers to share the constraints of devices while attaching >> >to the dmabuf buffer. >> > >> >

Re: [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-02-11 Thread Russell King - ARM Linux
On Wed, Feb 11, 2015 at 09:28:37AM +0100, Marek Szyprowski wrote: > Hello, > > On 2015-01-27 09:25, Sumit Semwal wrote: > >Add some helpers to share the constraints of devices while attaching > >to the dmabuf buffer. > > > >At each attach, the constraints are calculated based on the following: > >

Re: [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-02-11 Thread Marek Szyprowski
Hello, On 2015-01-27 09:25, Sumit Semwal wrote: Add some helpers to share the constraints of devices while attaching to the dmabuf buffer. At each attach, the constraints are calculated based on the following: - max_segment_size, max_segment_count, segment_boundary_mask from device_dma_para

Re: [Linaro-mm-sig] [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-02-03 Thread Russell King - ARM Linux
On Tue, Feb 03, 2015 at 10:42:26PM +0100, Arnd Bergmann wrote: > Right, if you have a private iommu, there is no problem. The tricky part > is using a single driver for the system-level translation and the gpu > private mappings when there is only one type of iommu in the system. You've got a prob

Re: [Linaro-mm-sig] [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-02-03 Thread Daniel Vetter
On Tue, Feb 3, 2015 at 10:42 PM, Arnd Bergmann wrote: >> Again assuming I'm not confused can't we just solve this by pushing the >> dma api abstraction down one layer for just the gpu, and let it use its >> private iommmu directly? Steps for binding a buffer would be: >> 1. dma_map_sg >> 2. Noodle

Re: [Linaro-mm-sig] [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-02-03 Thread Arnd Bergmann
On Tuesday 03 February 2015 12:35:34 Rob Clark wrote: > > I can't think of cases outside of GPU's.. if it were more common I'd > be in favor of teaching dma api about multiple contexts, but right now > I think that would just amount to forcing a lot of churn on everyone > else for the benefit of

Re: [Linaro-mm-sig] [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-02-03 Thread Arnd Bergmann
On Tuesday 03 February 2015 21:04:35 Daniel Vetter wrote: > - On many soc people love to reuse iommus with the same or similar > interface all over the place. The solution thus far adopted on arm > platforms is to write an iommu driver for those and then implement the > dma-api on top of thi

Re: [Linaro-mm-sig] [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-02-03 Thread Daniel Vetter
On Tue, Feb 03, 2015 at 12:35:34PM -0500, Rob Clark wrote: > On Tue, Feb 3, 2015 at 11:58 AM, Russell King - ARM Linux > wrote: > > > > Okay, but switching contexts is not something which the DMA API has > > any knowledge of (so it can't know which context to associate with > > which mapping.) Wh

Re: [Linaro-mm-sig] [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-02-03 Thread Daniel Vetter
On Tue, Feb 03, 2015 at 05:36:59PM +0100, Arnd Bergmann wrote: > On Tuesday 03 February 2015 11:22:01 Rob Clark wrote: > > On Tue, Feb 3, 2015 at 11:12 AM, Arnd Bergmann wrote: > > > I agree for the case you are describing here. From what I understood > > > from Rob was that he is looking at somet

Re: [Linaro-mm-sig] [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-02-03 Thread Rob Clark
On Tue, Feb 3, 2015 at 11:58 AM, Russell King - ARM Linux wrote: > > Okay, but switching contexts is not something which the DMA API has > any knowledge of (so it can't know which context to associate with > which mapping.) While it knows which device, it has no knowledge > (nor is there any way

Re: [Linaro-mm-sig] [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-02-03 Thread Russell King - ARM Linux
On Tue, Feb 03, 2015 at 11:22:01AM -0500, Rob Clark wrote: > On Tue, Feb 3, 2015 at 11:12 AM, Arnd Bergmann wrote: > > I agree for the case you are describing here. From what I understood > > from Rob was that he is looking at something more like: > > > > Fig 3 > > CPU--L1cache--L2cache--Memory--I

Re: [Linaro-mm-sig] [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-02-03 Thread Russell King - ARM Linux
On Tue, Feb 03, 2015 at 05:12:40PM +0100, Arnd Bergmann wrote: > On Tuesday 03 February 2015 15:54:04 Russell King - ARM Linux wrote: > > On Tue, Feb 03, 2015 at 04:31:13PM +0100, Arnd Bergmann wrote: > > > The dma_map_* interfaces assign the virtual addresses internally, > > > using typically eith

Re: [Linaro-mm-sig] [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-02-03 Thread Arnd Bergmann
On Tuesday 03 February 2015 11:22:01 Rob Clark wrote: > On Tue, Feb 3, 2015 at 11:12 AM, Arnd Bergmann wrote: > > I agree for the case you are describing here. From what I understood > > from Rob was that he is looking at something more like: > > > > Fig 3 > > CPU--L1cache--L2cache--Memory--IOMMU-

Re: [Linaro-mm-sig] [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-02-03 Thread Rob Clark
On Tue, Feb 3, 2015 at 11:12 AM, Arnd Bergmann wrote: > I agree for the case you are describing here. From what I understood > from Rob was that he is looking at something more like: > > Fig 3 > CPU--L1cache--L2cache--Memory--IOMMU-device > > where the IOMMU controls one or more contexts per d

Re: [Linaro-mm-sig] [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-02-03 Thread Arnd Bergmann
On Tuesday 03 February 2015 15:54:04 Russell King - ARM Linux wrote: > On Tue, Feb 03, 2015 at 04:31:13PM +0100, Arnd Bergmann wrote: > > The dma_map_* interfaces assign the virtual addresses internally, > > using typically either a global address space for all devices, or one > > address space per

Re: [Linaro-mm-sig] [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-02-03 Thread Russell King - ARM Linux
On Tue, Feb 03, 2015 at 04:31:13PM +0100, Arnd Bergmann wrote: > On Tuesday 03 February 2015 15:22:05 Russell King - ARM Linux wrote: > > Don't we already have those in the DMA API? dma_sync_*() ? > > > > dma_map_sg() - sets up the system MMU and deals with initial cache > > coherency handling. D

Re: [Linaro-mm-sig] [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-02-03 Thread Arnd Bergmann
On Tuesday 03 February 2015 15:22:05 Russell King - ARM Linux wrote: > On Tue, Feb 03, 2015 at 03:52:48PM +0100, Arnd Bergmann wrote: > > On Tuesday 03 February 2015 14:41:09 Russell King - ARM Linux wrote: > > > I'd go as far as saying that the "DMA API on top of IOMMU" is more > > > intended to b

Re: [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-02-03 Thread Rob Clark
On Tue, Feb 3, 2015 at 9:52 AM, Arnd Bergmann wrote: > On Tuesday 03 February 2015 14:41:09 Russell King - ARM Linux wrote: >> On Tue, Feb 03, 2015 at 03:17:27PM +0100, Arnd Bergmann wrote: >> > On Tuesday 03 February 2015 09:04:03 Rob Clark wrote: >> > > Since I'm stuck w/ an iommu, instead of bu

Re: [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-02-03 Thread Russell King - ARM Linux
On Tue, Feb 03, 2015 at 03:52:48PM +0100, Arnd Bergmann wrote: > On Tuesday 03 February 2015 14:41:09 Russell King - ARM Linux wrote: > > I'd go as far as saying that the "DMA API on top of IOMMU" is more > > intended to be for a system IOMMU for the bus in question, rather > > than a device-level

Re: [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-02-03 Thread Rob Clark
On Tue, Feb 3, 2015 at 9:41 AM, Russell King - ARM Linux wrote: > On Tue, Feb 03, 2015 at 03:17:27PM +0100, Arnd Bergmann wrote: >> On Tuesday 03 February 2015 09:04:03 Rob Clark wrote: >> > Since I'm stuck w/ an iommu, instead of built in mmu, my plan was to >> > drop use of dma-mapping entirely

Re: [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-02-03 Thread Russell King - ARM Linux
On Tue, Feb 03, 2015 at 09:44:57AM -0500, Rob Clark wrote: > On Tue, Feb 3, 2015 at 9:37 AM, Russell King - ARM Linux > wrote: > > On Tue, Feb 03, 2015 at 09:04:03AM -0500, Rob Clark wrote: > >> Since I'm stuck w/ an iommu, instead of built in mmu, my plan was to > >> drop use of dma-mapping entir

Re: [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-02-03 Thread Arnd Bergmann
On Tuesday 03 February 2015 14:41:09 Russell King - ARM Linux wrote: > On Tue, Feb 03, 2015 at 03:17:27PM +0100, Arnd Bergmann wrote: > > On Tuesday 03 February 2015 09:04:03 Rob Clark wrote: > > > Since I'm stuck w/ an iommu, instead of built in mmu, my plan was to > > > drop use of dma-mapping en

Re: [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-02-03 Thread Rob Clark
On Tue, Feb 3, 2015 at 9:37 AM, Russell King - ARM Linux wrote: > On Tue, Feb 03, 2015 at 09:04:03AM -0500, Rob Clark wrote: >> Since I'm stuck w/ an iommu, instead of built in mmu, my plan was to >> drop use of dma-mapping entirely (incl the current call to dma_map_sg, >> which I just need until

Re: [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-02-03 Thread Russell King - ARM Linux
On Tue, Feb 03, 2015 at 03:17:27PM +0100, Arnd Bergmann wrote: > On Tuesday 03 February 2015 09:04:03 Rob Clark wrote: > > Since I'm stuck w/ an iommu, instead of built in mmu, my plan was to > > drop use of dma-mapping entirely (incl the current call to dma_map_sg, > > which I just need until we c

Re: [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-02-03 Thread Russell King - ARM Linux
On Tue, Feb 03, 2015 at 09:04:03AM -0500, Rob Clark wrote: > Since I'm stuck w/ an iommu, instead of built in mmu, my plan was to > drop use of dma-mapping entirely (incl the current call to dma_map_sg, > which I just need until we can use drm_cflush on arm), and > attach/detach iommu domains direc

Re: [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-02-03 Thread Russell King - ARM Linux
On Tue, Feb 03, 2015 at 02:28:26PM +0100, Christian Gmeiner wrote: > 2015-02-03 13:28 GMT+01:00 Russell King - ARM Linux : > > What I've found with *my* etnaviv drm implementation (not Christian's - I > > found it impossible to work with Christian, especially with the endless > > "msm doesn't do it

Re: [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-02-03 Thread Rob Clark
On Tue, Feb 3, 2015 at 7:28 AM, Russell King - ARM Linux wrote: > On Tue, Feb 03, 2015 at 08:48:56AM +0100, Daniel Vetter wrote: >> On Mon, Feb 02, 2015 at 03:30:21PM -0500, Rob Clark wrote: >> > On Mon, Feb 2, 2015 at 11:54 AM, Daniel Vetter wrote: >> > >> My initial thought is for dma-buf to no

Re: [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-02-03 Thread Arnd Bergmann
On Tuesday 03 February 2015 09:04:03 Rob Clark wrote: > On Tue, Feb 3, 2015 at 2:48 AM, Daniel Vetter wrote: > > On Mon, Feb 02, 2015 at 03:30:21PM -0500, Rob Clark wrote: > >> On Mon, Feb 2, 2015 at 11:54 AM, Daniel Vetter wrote: > >> >> My initial thought is for dma-buf to not try to prevent so

Re: [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-02-03 Thread Rob Clark
On Tue, Feb 3, 2015 at 2:48 AM, Daniel Vetter wrote: > On Mon, Feb 02, 2015 at 03:30:21PM -0500, Rob Clark wrote: >> On Mon, Feb 2, 2015 at 11:54 AM, Daniel Vetter wrote: >> >> My initial thought is for dma-buf to not try to prevent something than >> >> an exporter can actually do.. I think the s

Re: [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-02-03 Thread Christian Gmeiner
2015-02-03 13:28 GMT+01:00 Russell King - ARM Linux : > On Tue, Feb 03, 2015 at 08:48:56AM +0100, Daniel Vetter wrote: >> On Mon, Feb 02, 2015 at 03:30:21PM -0500, Rob Clark wrote: >> > On Mon, Feb 2, 2015 at 11:54 AM, Daniel Vetter wrote: >> > >> My initial thought is for dma-buf to not try to pr

Re: [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-02-03 Thread Daniel Vetter
On Tue, Feb 03, 2015 at 12:28:14PM +, Russell King - ARM Linux wrote: > On Tue, Feb 03, 2015 at 08:48:56AM +0100, Daniel Vetter wrote: > > On Mon, Feb 02, 2015 at 03:30:21PM -0500, Rob Clark wrote: > > > On Mon, Feb 2, 2015 at 11:54 AM, Daniel Vetter wrote: > > > >> My initial thought is for d

Re: [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-02-03 Thread Russell King - ARM Linux
On Tue, Feb 03, 2015 at 08:48:56AM +0100, Daniel Vetter wrote: > On Mon, Feb 02, 2015 at 03:30:21PM -0500, Rob Clark wrote: > > On Mon, Feb 2, 2015 at 11:54 AM, Daniel Vetter wrote: > > >> My initial thought is for dma-buf to not try to prevent something than > > >> an exporter can actually do.. I

Re: [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-02-02 Thread Daniel Vetter
On Mon, Feb 02, 2015 at 05:36:10PM -0500, Rob Clark wrote: > well, I guess anyways when it comes to sharing buffers, it won't be > the vram placement of the bo that gets shared ;-) Actually that's pretty much what I'd like to be able to do for i915. Except that vram is just a specially protected c

Re: [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-02-02 Thread Daniel Vetter
On Mon, Feb 02, 2015 at 03:30:21PM -0500, Rob Clark wrote: > On Mon, Feb 2, 2015 at 11:54 AM, Daniel Vetter wrote: > >> My initial thought is for dma-buf to not try to prevent something than > >> an exporter can actually do.. I think the scenario you describe could > >> be handled by two sg-lists,

Re: [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-02-02 Thread Daniel Vetter
On Mon, Feb 02, 2015 at 09:46:16PM +, Russell King - ARM Linux wrote: > On Mon, Feb 02, 2015 at 03:30:21PM -0500, Rob Clark wrote: > > On Mon, Feb 2, 2015 at 11:54 AM, Daniel Vetter wrote: > > >> My initial thought is for dma-buf to not try to prevent something than > > >> an exporter can actu

Re: [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-02-02 Thread Rob Clark
On Mon, Feb 2, 2015 at 4:46 PM, Russell King - ARM Linux wrote: > On Mon, Feb 02, 2015 at 03:30:21PM -0500, Rob Clark wrote: >> On Mon, Feb 2, 2015 at 11:54 AM, Daniel Vetter wrote: >> >> My initial thought is for dma-buf to not try to prevent something than >> >> an exporter can actually do.. I

Re: [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-02-02 Thread Russell King - ARM Linux
On Mon, Feb 02, 2015 at 03:30:21PM -0500, Rob Clark wrote: > On Mon, Feb 2, 2015 at 11:54 AM, Daniel Vetter wrote: > >> My initial thought is for dma-buf to not try to prevent something than > >> an exporter can actually do.. I think the scenario you describe could > >> be handled by two sg-lists,

Re: [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-02-02 Thread Rob Clark
On Mon, Feb 2, 2015 at 11:54 AM, Daniel Vetter wrote: >> My initial thought is for dma-buf to not try to prevent something than >> an exporter can actually do.. I think the scenario you describe could >> be handled by two sg-lists, if the exporter was clever enough. > > That's already needed, each

Re: [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-02-02 Thread Daniel Vetter
On Thu, Jan 29, 2015 at 05:18:33PM -0500, Rob Clark wrote: > On Thu, Jan 29, 2015 at 2:26 PM, Russell King - ARM Linux > wrote: > > On Thu, Jan 29, 2015 at 01:52:09PM -0500, Rob Clark wrote: > >> Quite possibly for some of these edge some of cases, some of the > >> dma-buf exporters are going to n

Re: [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-02-01 Thread Sumit Semwal
Hi Russell, On 30 January 2015 at 00:56, Russell King - ARM Linux wrote: > On Thu, Jan 29, 2015 at 01:52:09PM -0500, Rob Clark wrote: >> Quite possibly for some of these edge some of cases, some of the >> dma-buf exporters are going to need to get more clever (ie. hand off >> different scatterlis

Re: [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-01-29 Thread Rob Clark
On Thu, Jan 29, 2015 at 5:31 PM, Russell King - ARM Linux wrote: > On Thu, Jan 29, 2015 at 05:18:33PM -0500, Rob Clark wrote: >> On Thu, Jan 29, 2015 at 2:26 PM, Russell King - ARM Linux >> wrote: >> > Now, if we're going to do the "more clever" thing you mention above, >> > that rather negates t

Re: [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-01-29 Thread Russell King - ARM Linux
On Thu, Jan 29, 2015 at 05:18:33PM -0500, Rob Clark wrote: > On Thu, Jan 29, 2015 at 2:26 PM, Russell King - ARM Linux > wrote: > > Now, if we're going to do the "more clever" thing you mention above, > > that rather negates the point of this two-part patch set, which is to > > provide the union o

Re: [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-01-29 Thread Rob Clark
On Thu, Jan 29, 2015 at 2:26 PM, Russell King - ARM Linux wrote: > On Thu, Jan 29, 2015 at 01:52:09PM -0500, Rob Clark wrote: >> Quite possibly for some of these edge some of cases, some of the >> dma-buf exporters are going to need to get more clever (ie. hand off >> different scatterlists to dif

Re: [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-01-29 Thread Russell King - ARM Linux
On Thu, Jan 29, 2015 at 01:52:09PM -0500, Rob Clark wrote: > Quite possibly for some of these edge some of cases, some of the > dma-buf exporters are going to need to get more clever (ie. hand off > different scatterlists to different clients). Although I think by far > the two common cases will b

Re: [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-01-29 Thread Rob Clark
On Thu, Jan 29, 2015 at 10:47 AM, Russell King - ARM Linux wrote: > On Thu, Jan 29, 2015 at 09:00:11PM +0530, Sumit Semwal wrote: >> So, short answer is, it is left to the exporter to decide. The dma-buf >> framework should not even attempt to decide or enforce any of the >> above. >> >> At each d

Re: [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-01-29 Thread Sumit Semwal
On 29 January 2015 at 21:17, Russell King - ARM Linux wrote: > On Thu, Jan 29, 2015 at 09:00:11PM +0530, Sumit Semwal wrote: >> So, short answer is, it is left to the exporter to decide. The dma-buf >> framework should not even attempt to decide or enforce any of the >> above. >> >> At each dma_bu

Re: [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-01-29 Thread Russell King - ARM Linux
On Thu, Jan 29, 2015 at 09:00:11PM +0530, Sumit Semwal wrote: > So, short answer is, it is left to the exporter to decide. The dma-buf > framework should not even attempt to decide or enforce any of the > above. > > At each dma_buf_attach(), there's a callback to the exporter, where > the exporter

Re: [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-01-29 Thread Sumit Semwal
Hi Russell! On 29 January 2015 at 20:09, Russell King - ARM Linux wrote: > On Tue, Jan 27, 2015 at 01:55:54PM +0530, Sumit Semwal wrote: >> +/* >> + * recalc_constraints - recalculates constraints for all attached devices; >> + * useful for detach() recalculation, and for dma_buf_recalc_constrai

Re: [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-01-29 Thread Russell King - ARM Linux
On Tue, Jan 27, 2015 at 01:55:54PM +0530, Sumit Semwal wrote: > +/* > + * recalc_constraints - recalculates constraints for all attached devices; > + * useful for detach() recalculation, and for dma_buf_recalc_constraints() > + * helper. > + * Returns recalculated constraints in recalc_cons, or

Re: [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-01-29 Thread Maarten Lankhorst
Op 27-01-15 om 09:25 schreef Sumit Semwal: > Add some helpers to share the constraints of devices while attaching > to the dmabuf buffer. > > At each attach, the constraints are calculated based on the following: > - max_segment_size, max_segment_count, segment_boundary_mask from >device_dma_pa

[RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms

2015-01-27 Thread Sumit Semwal
Add some helpers to share the constraints of devices while attaching to the dmabuf buffer. At each attach, the constraints are calculated based on the following: - max_segment_size, max_segment_count, segment_boundary_mask from device_dma_parameters. In case the attaching device's constraints