Hi Deb,
On 03/10/2023 01:51, Deborah Brouwer wrote:
> On Wed, Sep 27, 2023 at 09:19:46AM +0200, Hans Verkuil wrote:
>> On 27/09/2023 01:29, Nicolas Dufresne wrote:
>>> Le vendredi 22 septembre 2023 à 09:33 +0200, Hans Verkuil a écrit :
>>>> On 21/09/2023 21:11, Nicolas Dufresne wrote:
>>>>> Le mercredi 20 septembre 2023 à 17:13 +0200, Hans Verkuil a écrit :
>>>>>> On 15/09/2023 23:11, Sebastian Fricke wrote:
>>>>>>> From: Nas Chung <nas.chung@xxxxxxxxxxxxxxx>
>>>>>>>
>>>>>>> Add the decoder and encoder implementing the v4l2
>>>>>>> API. This patch also adds the Makefile and the VIDEO_WAVE_VPU config
>>>>>>>
>>>>>>> Signed-off-by: Sebastian Fricke <sebastian.fricke@xxxxxxxxxxxxx>
>>>>>>> Signed-off-by: Nicolas Dufresne <nicolas.dufresne@xxxxxxxxxxxxx>
>>>>>>> Signed-off-by: Robert Beckett <bob.beckett@xxxxxxxxxxxxx>
>>>>>>> Signed-off-by: Dafna Hirschfeld <dafna.hirschfeld@xxxxxxxxxxxxx>
>>>>>>> Signed-off-by: Nas Chung <nas.chung@xxxxxxxxxxxxxxx>
>>>>>>> ---
>>>>>>> drivers/media/platform/chips-media/Kconfig | 1 +
>>>>>>> drivers/media/platform/chips-media/Makefile | 1 +
>>>>>>> drivers/media/platform/chips-media/wave5/Kconfig | 12 +
>>>>>>> drivers/media/platform/chips-media/wave5/Makefile | 10 +
>>>>>>> .../platform/chips-media/wave5/wave5-helper.c | 196 ++
>>>>>>> .../platform/chips-media/wave5/wave5-helper.h | 30 +
>>>>>>> .../platform/chips-media/wave5/wave5-vpu-dec.c | 1965 ++++++++++++++++++++
>>>>>>> .../platform/chips-media/wave5/wave5-vpu-enc.c | 1825 ++++++++++++++++++
>>>>>>> .../media/platform/chips-media/wave5/wave5-vpu.c | 331 ++++
>>>>>>> .../media/platform/chips-media/wave5/wave5-vpu.h | 83 +
>>>>>>> 10 files changed, 4454 insertions(+)
>>>>>>>
>>>>
>>>> <snip>
>>>>
>>>>>>> +static int wave5_vpu_dec_set_eos_on_firmware(struct vpu_instance *inst)
>>>>>>> +{
>>>>>>> + int ret;
>>>>>>> +
>>>>>>> + ret = wave5_vpu_dec_update_bitstream_buffer(inst, 0);
>>>>>>> + if (ret) {
>>>>>>> + dev_err(inst->dev->dev,
>>>>>>> + "Setting EOS for the bitstream, fail: %d\n", ret);
>>>>>>
>>>>>> Is this an error due to a driver problem, or because a bad bitstream is
>>>>>> fed from userspace? In the first case, dev_err would be right, in the
>>>>>> second dev_dbg would be more appropriate. Bad userspace input should not
>>>>>> spam the kernel log in general.
>>>>>
>>>>> Its the first. To set the EOS flag, a command is sent to the firmware. That
>>>>> command may never return (timeout) or may report an error. For this specific
>>>>> command, if that happens we are likely facing firmware of driver problem (or
>>>>> both).
>>>>
>>>> OK, I'd add that as a comment here as this is unexpected behavior.
>>>>
>>>>>
>>>>>>
>>>>>>> + return ret;
>>>>>>> + }
>>>>>>> + return 0;
>>>>>>> +}
>>>>
>>>> <snip>
>>>>
>>>>>>> +static int wave5_vpu_dec_create_bufs(struct file *file, void *priv,
>>>>>>> + struct v4l2_create_buffers *create)
>>>>>>> +{
>>>>>>> + struct v4l2_format *f = &create->format;
>>>>>>> +
>>>>>>> + if (f->type == V4L2_BUF_TYPE_VIDEO_CAPTURE)
>>>>>>> + return -ENOTTY;
>>>>>>
>>>>>> Huh? Why is this needed?
>>>>>
>>>>> Minimally a comment should be added. The why is that we support CREATE_BUF for
>>>>> OUTPUT queue (bitstream) but not for CAPTURE queues. This is simply not
>>>>> supported by Wave5 firmware. Do you have any suggestion how this asymmetry can
>>>>> be implemented better ?
>>>>
>>>> Certainly not with ENOTTY: the ioctl exists, it is just not supported for
>>>> CAPTURE queues.
>>>>
>>>> How about -EPERM? And document this error as well in the VIDIOC_CREATE_BUFS
>>>> documentation. And you want a dev_dbg here too.
>>>
>>> The suggestion cannot be used since there is documentation for that one already,
>>> and it does not match "unsupported".
>>>
>>> "Permission denied. Can be returned if the device needs write permission, or
>>> some special capabilities is needed (e. g. root)"
>>>
>>> What about using the most logical error code, which name is actually obvious,
>>> like ENOTSUP ?
>>>
>>> #define ENOTSUPP 524 /* Operation is not supported */
>>>
>>
>> Let's go with EOPNOTSUPP. That seems to be the more commonly used error
>> code in drivers.
>
> Hi Hans,
>
> Sorry to belabour this issue but when I change the return value
> to EOPNOTSUPP, it now causes v4l2-compliance to fail because
> v4l2-test-buffers.cpp expects ENOTTY if CREATE_BUFS is not supported.
>
> We didn't get this warning before because there was a typo in the
> buffer check and it was only checking for single-planar buffers.
>
> How would you prefer to handle this? The options seem like
> keep ENOTTY in this driver or
> patch v4l2-compliance to warn if it also receives EOPNOTSUPP?
You patch v4l2-compliance. It makes sense: we're making a uAPI modification,
so that implies changes to v4l2-compliance.
So v4l2-compliance needs to understand EOPNOTSUPP for CREATE_BUFS: if it is
returned it has to check that it is used correctly: so there has to be at
least one buffer type for which CREATE_BUFS actually works. In other words,
v4l2-compliance must check that EOPNOTSUPP isn't used as a replacement
for ENOTTY.
This can be done in testReqBufs().
Regards,
Hans
