On 11/20/2015 05:14 PM, Ran Shalit wrote:
>>>
>>> 1. I tried to understand the code implementation of videobuf2 with
>>> regards to read():
>>> read() ->
>>> vb2_read() ->
>>> __vb2_perform_fileio()->
>>> vb2_internal_dqbuf() & copy_to_user()
>>>
>>> Where is the actual
>>
>> 1. I tried to understand the code implementation of videobuf2 with
>> regards to read():
>> read() ->
>> vb2_read() ->
>> __vb2_perform_fileio()->
>> vb2_internal_dqbuf() & copy_to_user()
>>
>> Where is the actual allocation of dma contiguous memory ? Is done with
On 11/20/2015 03:49 PM, Ran Shalit wrote:
> Hello,
>
>
>
>>
>> No. All video capture/output devices all use DMA since it would be
>> prohibitively
>> expensive for the CPU to do otherwise. So just dig in and implement it.
>
> I am trying to better understand how read() operation actually use t
Hello,
>
> No. All video capture/output devices all use DMA since it would be
> prohibitively
> expensive for the CPU to do otherwise. So just dig in and implement it.
I am trying to better understand how read() operation actually use the
dma, but I can't yet understand it from code.
>
> No.
On Tue, Nov 17, 2015 at 3:54 PM, Hans Verkuil wrote:
> On 11/17/15 14:15, Ran Shalit wrote:
>> On Tue, Nov 17, 2015 at 9:53 AM, Hans Verkuil wrote:
>>> On 11/17/2015 08:39 AM, Ran Shalit wrote:
Hello,
I intend to use cobalt driver as a refence for new pci v4l2 driver,
which is
On 11/17/15 14:15, Ran Shalit wrote:
> On Tue, Nov 17, 2015 at 9:53 AM, Hans Verkuil wrote:
>> On 11/17/2015 08:39 AM, Ran Shalit wrote:
>>> Hello,
>>>
>>> I intend to use cobalt driver as a refence for new pci v4l2 driver,
>>> which is required to use several input simultaneously. for this cobalt
> Is the cobalt or other pci v4l device have the chip datasheet
> available so that we can do a reverse engineering and gain more
> understanding about the register read/write for the dma transactions ?
> I made a search but it seems that the PCIe chip datasheet for these
> devices is not available
On Tue, Nov 17, 2015 at 9:53 AM, Hans Verkuil wrote:
> On 11/17/2015 08:39 AM, Ran Shalit wrote:
>> Hello,
>>
>> I intend to use cobalt driver as a refence for new pci v4l2 driver,
>> which is required to use several input simultaneously. for this cobalt
>> seems like a best starting point.
>> rea
On 11/17/2015 08:39 AM, Ran Shalit wrote:
> Hello,
>
> I intend to use cobalt driver as a refence for new pci v4l2 driver,
> which is required to use several input simultaneously. for this cobalt
> seems like a best starting point.
> read/write streaming will probably be suffecient (at least for t
Hello,
I intend to use cobalt driver as a refence for new pci v4l2 driver,
which is required to use several input simultaneously. for this cobalt
seems like a best starting point.
read/write streaming will probably be suffecient (at least for the
dirst debugging).
The configuration in my cast is i
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