Laurent -
On 03/18/15 07:39, Laurent Pinchart wrote:
Hi Tim,
On Tuesday 17 March 2015 17:57:30 Tim Nordell wrote:
On 04/21/14 07:29, Laurent Pinchart wrote:
Replace the custom buffers queue implementation with a videobuf2 queue.
Signed-off-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
I realize this is late (it's in the kernel now), but I'm noticing that
this does not appear to properly support the scatter-gather buffers that
were previously supported as far as I recall (and can tell with what was
removed with this patch), especially when using USERPTR. You can
observe this using "yavta" with the -u parameter. Can you confirm if
this works for you? I get the following output from the kernel when
attempting to stream a 640x480 UYVY framebuffer:
[ 111.381256] contiguous mapping is too small 589824/614400
The OMAP3 ISP uses an IOMMU, physically non-contiguous buffers should thus be
mapped contiguously into the device memory space. I haven't tried USERPTR
support recently, but this surprises me. It requires investigation. Could you
give it a try ?
That's why I wrote the e-mail since I did give it a try. It doesn't
work in kernel v3.19 as expected. I'm using a BT.656 device (and with
the patches I submitted last week since it didn't work for my device
without those that I wrote), so it's a little harder to go back to the
exact patch that causes it to fail (since I believe it's this patch
which is pre-BT.656 support) but I would guess that it's the one I
replied to here.
The videobuf2-dma-contig framework is what is emitting this error, and
part of it's framework checks that the buffer is fully contiguous in
memory rather than doing scatter-gather. The function
"vb2_dc_get_contiguous_size(...)" is what finds the full contiguous area
of the buffer and reports back internally how much is available in a
row. Would videobuf2-dma-sg have been a better choice here? I tried a
naive conversion to that (that is, I'm sure I messed something up), but
it yielded the kernel spewing messages about "Address Hole seen by CAM"
from the omap_l3_smx driver.
- Tim
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