media: vivid: add module option to set request support mode

Currently vivid supports the Request API, but it also sets
min_buffers_needed in the vb2 queue. But the combination of
support_requests and min_buffers_needed is not allowed due to
the fact that vb2_core_qbuf() isn't supposed to fail when called
from the request framework. And if min_buffers_needed > 0, then
is can call start_streaming() which definitely can fail.

With the new module option you can control if requests are not
allowed (min_buffers_needed is 2 in that case), optionally allowed
or are required. In the latter two cases min_buffers_needed is set
to 0.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
This commit is contained in:
Hans Verkuil 2021-07-29 15:36:26 +02:00 committed by Mauro Carvalho Chehab
parent 4787db29f8
commit b72dd0f390

View file

@ -177,6 +177,15 @@ MODULE_PARM_DESC(cache_hints, " user-space cache hints, default is 0.\n"
"\t\t 0 == forbid\n"
"\t\t 1 == allow");
static unsigned int supports_requests[VIVID_MAX_DEVS] = {
[0 ... (VIVID_MAX_DEVS - 1)] = 1
};
module_param_array(supports_requests, uint, NULL, 0444);
MODULE_PARM_DESC(supports_requests, " support for requests, default is 1.\n"
"\t\t 0 == no support\n"
"\t\t 1 == supports requests\n"
"\t\t 2 == requires requests");
static struct vivid_dev *vivid_devs[VIVID_MAX_DEVS];
const struct v4l2_rect vivid_min_rect = {
@ -883,10 +892,11 @@ static int vivid_create_queue(struct vivid_dev *dev,
q->mem_ops = allocators[dev->inst] == 1 ? &vb2_dma_contig_memops :
&vb2_vmalloc_memops;
q->timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;
q->min_buffers_needed = min_buffers_needed;
q->min_buffers_needed = supports_requests[dev->inst] ? 0 : min_buffers_needed;
q->lock = &dev->mutex;
q->dev = dev->v4l2_dev.dev;
q->supports_requests = true;
q->supports_requests = supports_requests[dev->inst];
q->requires_requests = supports_requests[dev->inst] >= 2;
q->allow_cache_hints = (cache_hints[dev->inst] == 1);
return vb2_queue_init(q);