about mmap dma-buf and sync

[Daniel Stone]

Hi,

On 24 August 2015 at 17:56, Thomas Hellstrom <thellstrom at vmware.com> wrote:
> On 08/24/2015 05:52 PM, Daniel Stone wrote:
>> I still don't think this ameliorates the need for batching: consider
>> the case where you update two disjoint screen regions and want them
>> both flushed. Either you issue two separate sync calls (which can be
>> disadvantageous performance-wise on some hardware / setups), or you
>> accumulate the regions and only flush later. So either two ioctls (one
>> in the style of dirtyfb and one to perform the sync/flush; you can
>> shortcut to assume the full buffer was damaged if the former is
>> missing), or one like this:
>>
>> struct dma_buf_sync_2d {
>>         enum dma_buf_sync_flags flags;
>>
>>         __u64 stride_bytes;
>>         __u32 bytes_per_pixel;
>>         __u32 num_regions;
>>
>>         struct {
>>                 __u64 x;
>>                 __u64 y;
>>                 __u64 width;
>>                 __u64 height;
>>         } regions[];
>> };
>>
>> Cheers,
>> Daniel
>
> Fine with me, although perhaps bytes_per_pixel is a bit redundant?

Redundant how? It's not implicit in stride.

Cheers,
Daniel