Hi Sumit and Pawel,
Please find comments below.
On 01/20/2012 11:41 AM, Sumit Semwal wrote:
On 20 January 2012 00:37, Pawel Osciak<pawel@xxxxxxxxxx> wrote:
Hi Sumit,
Thank you for your work. Please find my comments below.
Hi Pawel,
Thank you for finding time for this review, and your comments :) - my
comments inline.
[Also, as an aside, Tomasz has also been working on the vb2 adaptation
to dma-buf, and his patches should be more comprehensive, in that he
is also planning to include 'vb2 as exporter' of dma-buf. He might
take and improve on this RFC, so it might be worthwhile to wait for
it?]
<snip>
struct vb2_mem_ops {
void *(*alloc)(void *alloc_ctx, unsigned long size);
@@ -65,6 +82,16 @@ struct vb2_mem_ops {
unsigned long size, int write);
void (*put_userptr)(void *buf_priv);
+ /* Comment from Rob Clark: XXX: I think the attach / detach could be handled
+ * in the vb2 core, and vb2_mem_ops really just need to get/put the
+ * sglist (and make sure that the sglist fits it's needs..)
+ */
I *strongly* agree with Rob here. Could you explain the reason behind
not doing this?
Allocator should ideally not have to be aware of attaching/detaching,
this is not specific to an allocator.
Ok, I thought we'll start with this version first, and then refine.
But you guys are right.
I think that it is not possible to move attach/detach to vb2-core. The
problem is that dma_buf_attach needs 'struct device' argument. This
pointer is not available in vb2-core. This pointer is delivered by
device's driver in "void *alloc_context".
Moving information about device would introduce new problems like:
- breaking layering in vb2
- some allocators like vb2-vmalloc do not posses any device related
attributes
Best regards,
Tomasz Stanislawski
--
Best regards,
Pawel Osciak
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