[PATCH] drm/vgem: drop DRIVER_PRIME

[Rob Clark]

On Thu, May 21, 2015 at 11:03 AM, Thomas Hellstrom
<thellstrom at vmware.com> wrote:
> Hi, Rob!
>
> On 05/21/2015 04:53 PM, Rob Clark wrote:
>> For actual sharing of buffers with other drivers (ie. actual hardware)
>> we'll need to pimp things out a bit better to deal w/ caching, multiple
>> memory domains, etc.  See thread:
>>
>>   https://urldefense.proofpoint.com/v2/url?u=http-3A__lists.freedesktop.org_archives_dri-2Ddevel_2015-2DMay_083160.html&d=AwIBAg&c=Sqcl0Ez6M0X8aeM67LKIiDJAXVeAw-YihVMNtXt-uEs&r=vpukPkBtpoNQp2IUKuFviOmPNYWVKmen3Jeeu55zmEA&m=hZDsGjgypZF71rQfORpnkvT34UoNymdOdW0M3RyIIpQ&s=6QpYr_rF5y3fBjm48gY5zTJp6Fu87bv2HJYGGJ7VX7s&e=
>>
>> But for the llvmpipe use-case this isn't a problem.  Nor do we really
>> need prime/dri3 (dri2 is sufficient).  So until the other issues are
>> sorted lets remove DRIVER_PRIME.
>>
>> NOTE this ends up leaving some basically dead code for prime import/
>> export (mostly because I was rushing to send this before a meeting).
>
> What worries me a little is what Daniel brought up in his commit
> message, that let's say in the end people add a reasonable interface to
> dma_buf mmap, vgem also needs a corresponding interface... Makes me
> think that the best solution for now
> is perhaps to revert it.

Well, I think that is solvable..  ie. when vgem regains PRIME support,
disallow mmap'ing of imported buffers (and disallow export?), and do
all cpu-prep/fini stuff via dmabuf handle, for example.

Without prime, vgem is at least for now useful for allocating a dumb
buffer and sharing it between X and client (for llvmpipe rendering).

BR,
-R

> /Thomas
>
>
>>
>> Signed-off-by: Rob Clark <robdclark at gmail.com>
>> ---
>> This is an alternative to removing vgem completely for 4.1, so that
>> llvmpipe work can get started in parallel with sorting out the other
>> issues for sw + hw access..
>>
>>  drivers/gpu/drm/vgem/vgem_drv.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/vgem/vgem_drv.c b/drivers/gpu/drm/vgem/vgem_drv.c
>> index cb3b435..b0316f9 100644
>> --- a/drivers/gpu/drm/vgem/vgem_drv.c
>> +++ b/drivers/gpu/drm/vgem/vgem_drv.c
>> @@ -302,7 +302,7 @@ static const struct file_operations vgem_driver_fops = {
>>  };
>>
>>  static struct drm_driver vgem_driver = {
>> -     .driver_features                = DRIVER_GEM | DRIVER_PRIME,
>> +     .driver_features                = DRIVER_GEM,
>>       .gem_free_object                = vgem_gem_free_object,
>>       .gem_vm_ops                     = &vgem_gem_vm_ops,
>>       .ioctls                         = vgem_ioctls,
>