Austin Yuan wrote:
> On Mon, Sep 15, 2008 at 9:24 PM, Thomas Hellström
> <[EMAIL PROTECTED]> wrote:
>
>> No. In fact there is no big change in usage pattern. Map / RW / Unmap is
>> there, except
>> it works without syncing. So to mimic the old behaviour you'd do
>>
>> map()
>> sync_for_cpu()
>> RW
>> release_from_cpu()
>> unmap()
>>
> TTM_BO_SYNCCPU is used for sync_for_cpu/release_from_cpu, right?
>
>
Yes, that's correct.
>> No, it will not. Note that this user interface suggestion is not set in
>> stone for each driver that
>> uses the TTM functionality, but the user interface TG will most probably use
>> for drivers not
>> deriving from GEM objects. The Radeon driver takes another approach and
>> derives BOs from
>> GEM objects and TTM BOs. In that case, the above user interface does not
>> apply.
>>
>> It's possible to create a shmem object without any pages backing it, if
>> needed.
>>
>> For user-buffers one should probably construct a separate driver-specific
>> IOCTL.
>> Since this is an RFC, and I agree that user-buffers are sometimes very handy
>> I'll include
>> a user-buffer create IOCTL and send out a new version.
>>
> Do you mean you will create a new IOCTL for user buffers? I originally
> wondered how to wrap my special BO creation request (BO pages are from
> a camera) into current TTM_BO_CREATE IOCTL following your proposal and
> not using GEM objects. If it also needs a new IOCTL, there will be 3
> IOCTLs for BO creation?
> In general, for my BO_create_from_camera_pages IOCTL, except
> size/placement(will be TT)/page_alignment, I need an extra private
> date which indicates a ID of camera pages. I like a "uint64_t
> priv_date" inserted into ttm_bo_create_req although it looks odd..
>
>
Austin, I don't think it's the right thing to add that to this
user-space interface.
If you want to target a specific driver with this functionality, just
add a driver-specific
ioctl that does exactly what you want.
It looks to me that the best way to do this for camera capture or for
v4l-like stuff is to have the
video input kernel driver allocate a buffer object from DRM, and DMA
directly into that
buffer object?
It would be better to try to set up such a generic interface within drm
itself,
/Thomas
> Just some thoughts
>
> Thanks
> Austin
>
> p.s. :
> struct ttm_bo_create_req {
> uint64_t size;
> uint32_t placement;
> uint32_t page_alignment;
> };
> vs.
> struct drm_bo_create_req {
> uint64_t mask;
> uint64_t size;
> uint64_t buffer_start;
> unsigned int hint;
> unsigned int page_alignment;
> };
>
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