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Message-ID: <155bb2c2-21b9-48d5-9615-7a44d4b6a590@ideasonboard.com>
Date: Thu, 11 Apr 2024 17:18:14 +0530
From: Umang Jain <umang.jain@...asonboard.com>
To: Tomi Valkeinen <tomi.valkeinen@...asonboard.com>
Cc: linux-media@...r.kernel.org, linux-kernel@...r.kernel.org,
Mauro Carvalho Chehab <mchehab@...nel.org>, Hans Verkuil
<hverkuil@...all.nl>, Laurent Pinchart <laurent.pinchart@...asonboard.com>,
Sakari Ailus <sakari.ailus@...ux.intel.com>
Subject: Re: [PATCH v3 9/9] media: subdev: Support single-stream case in
v4l2_subdev_enable/disable_streams()
Hi Tomi,
On 11/04/24 4:37 pm, Tomi Valkeinen wrote:
> On 11/04/2024 14:02, Umang Jain wrote:
>> Hi Tomi,
>>
>> On 10/04/24 6:05 pm, Tomi Valkeinen wrote:
>>> At the moment the v4l2_subdev_enable/disable_streams() functions call
>>> fallback helpers to handle the case where the subdev only implements
>>> .s_stream(), and the main function handles the case where the subdev
>>> implements streams (V4L2_SUBDEV_FL_STREAMS, which implies
>>> .enable/disable_streams()).
>>>
>>> What is missing is support for subdevs which do not implement streams
>>> support, but do implement .enable/disable_streams(). Example cases of
>>> these subdevices are single-stream cameras, where using
>>> .enable/disable_streams() is not required but helps us remove the users
>>> of the legacy .s_stream(), and subdevices with multiple source pads
>>> (but
>>> single stream per pad), where .enable/disable_streams() allows the
>>> subdevice to control the enable/disable state per pad.
>>>
>>> The two single-streams cases (.s_stream() and
>>> .enable/disable_streams())
>>> are very similar, and with small changes we can change the
>>> v4l2_subdev_enable/disable_streams() functions to support all three
>>> cases, without needing separate fallback functions.
>>>
>>> A few potentially problematic details, though:
>>
>> Does this mean the patch needs to be worked upon more ?
>
> I don't see the two issues below as blockers.
>
>> I quickly tested the series by applying it locally with my use case
>> of IMX283 .enable/disable streams and s_stream as the helper function
>> and it seems I am still seeing the same behaviour as before (i.e. not
>> being streamed) and have to carry the workaround as mentioned in [1]
>> **NOTE**
>
> Ok... Then something bugs here, as it is supposed to fix the problem.
> Can you trace the code a bit to see where it goes wrong?
>
> The execution should go to the "if (!(sd->flags &
> V4L2_SUBDEV_FL_STREAMS))" blocks in v4l2_subdev_collect_streams() and
> v4l2_subdev_set_streams_enabled(),
The execution is not reaching in v4l2_subdev_collect streams() even, it
returns at
if (!streams_mask)
return 0;
in v4l2_subdev_enable_streams()
Refer to : https://paste.debian.net/1313760/
My tree is based on v6.8 currently, but the series applies cleanly, so I
have not introduced any rebase artifacts. If you think, v6.8 might be
causing issues, I'll then try to test on RPi 5 with the latest media
tree perhaps.
>
> Tomi
>
>>
>> [1]
>> https://lore.kernel.org/linux-media/20240313070705.91140-1-umang.jain@ideasonboard.com/
>>
>>>
>>> - For the single-streams cases we use sd->enabled_pads field, which
>>> limits the number of pads for the subdevice to 64. For simplicity I
>>> added the check for this limitation to the beginning of the
>>> function,
>>> and it also applies to the streams case.
>>>
>>> - The fallback functions only allowed the target pad to be a source
>>> pad.
>>> It is not very clear to me why this check was needed, but it was not
>>> needed in the streams case. However, I doubt the
>>> v4l2_subdev_enable/disable_streams() code has ever been tested with
>>> sink pads, so to be on the safe side, I added the same check
>>> to the v4l2_subdev_enable/disable_streams() functions.
>>>
>>> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@...asonboard.com>
>>> ---
>>> drivers/media/v4l2-core/v4l2-subdev.c | 187
>>> ++++++++++++++--------------------
>>> 1 file changed, 79 insertions(+), 108 deletions(-)
>>>
>>> diff --git a/drivers/media/v4l2-core/v4l2-subdev.c
>>> b/drivers/media/v4l2-core/v4l2-subdev.c
>>> index 0d376d72ecc7..4a73886741f9 100644
>>> --- a/drivers/media/v4l2-core/v4l2-subdev.c
>>> +++ b/drivers/media/v4l2-core/v4l2-subdev.c
>>> @@ -2106,6 +2106,13 @@ static void
>>> v4l2_subdev_collect_streams(struct v4l2_subdev *sd,
>>> u64 *found_streams,
>>> u64 *enabled_streams)
>>> {
>>> + if (!(sd->flags & V4L2_SUBDEV_FL_STREAMS)) {
>>> + *found_streams = BIT_ULL(0);
>>> + if (sd->enabled_pads & BIT_ULL(pad))
>>> + *enabled_streams = BIT_ULL(0);
>>> + return;
>>> + }
>>> +
>>> *found_streams = 0;
>>> *enabled_streams = 0;
>>> @@ -2127,6 +2134,14 @@ static void
>>> v4l2_subdev_set_streams_enabled(struct v4l2_subdev *sd,
>>> u32 pad, u64 streams_mask,
>>> bool enabled)
>>> {
>>> + if (!(sd->flags & V4L2_SUBDEV_FL_STREAMS)) {
>>> + if (enabled)
>>> + sd->enabled_pads |= BIT_ULL(pad);
>>> + else
>>> + sd->enabled_pads &= ~BIT_ULL(pad);
>>> + return;
>>> + }
>>> +
>>> for (unsigned int i = 0; i <
>>> state->stream_configs.num_configs; ++i) {
>>> struct v4l2_subdev_stream_config *cfg =
>>> &state->stream_configs.configs[i];
>>> @@ -2136,51 +2151,6 @@ static void
>>> v4l2_subdev_set_streams_enabled(struct v4l2_subdev *sd,
>>> }
>>> }
>>> -static int v4l2_subdev_enable_streams_fallback(struct v4l2_subdev
>>> *sd, u32 pad,
>>> - u64 streams_mask)
>>> -{
>>> - struct device *dev = sd->entity.graph_obj.mdev->dev;
>>> - int ret;
>>> -
>>> - /*
>>> - * The subdev doesn't implement pad-based stream enable, fall back
>>> - * to the .s_stream() operation.
>>> - */
>>> - if (!(sd->entity.pads[pad].flags & MEDIA_PAD_FL_SOURCE))
>>> - return -EOPNOTSUPP;
>>> -
>>> - /*
>>> - * .s_stream() means there is no streams support, so only
>>> allowed stream
>>> - * is the implicit stream 0.
>>> - */
>>> - if (streams_mask != BIT_ULL(0))
>>> - return -EOPNOTSUPP;
>>> -
>>> - /*
>>> - * We use a 64-bit bitmask for tracking enabled pads, so only
>>> subdevices
>>> - * with 64 pads or less can be supported.
>>> - */
>>> - if (pad >= sizeof(sd->enabled_pads) * BITS_PER_BYTE)
>>> - return -EOPNOTSUPP;
>>> -
>>> - if (sd->enabled_pads & BIT_ULL(pad)) {
>>> - dev_dbg(dev, "pad %u already enabled on %s\n",
>>> - pad, sd->entity.name);
>>> - return -EALREADY;
>>> - }
>>> -
>>> - /* Start streaming when the first pad is enabled. */
>>> - if (!sd->enabled_pads) {
>>> - ret = v4l2_subdev_call(sd, video, s_stream, 1);
>>> - if (ret)
>>> - return ret;
>>> - }
>>> -
>>> - sd->enabled_pads |= BIT_ULL(pad);
>>> -
>>> - return 0;
>>> -}
>>> -
>>> int v4l2_subdev_enable_streams(struct v4l2_subdev *sd, u32 pad,
>>> u64 streams_mask)
>>> {
>>> @@ -2189,21 +2159,33 @@ int v4l2_subdev_enable_streams(struct
>>> v4l2_subdev *sd, u32 pad,
>>> bool already_streaming;
>>> u64 enabled_streams;
>>> u64 found_streams;
>>> + bool use_s_stream;
>>> int ret;
>>> /* A few basic sanity checks first. */
>>> if (pad >= sd->entity.num_pads)
>>> return -EINVAL;
>>> + if (!(sd->entity.pads[pad].flags & MEDIA_PAD_FL_SOURCE))
>>> + return -EOPNOTSUPP;
>>> +
>>> + /*
>>> + * We use a 64-bit bitmask for tracking enabled pads, so only
>>> subdevices
>>> + * with 64 pads or less can be supported.
>>> + */
>>> + if (pad >= sizeof(sd->enabled_pads) * BITS_PER_BYTE)
>>> + return -EOPNOTSUPP;
>>> +
>>> if (!streams_mask)
>>> return 0;
>>> /* Fallback on .s_stream() if .enable_streams() isn't
>>> available. */
>>> - if (!v4l2_subdev_has_op(sd, pad, enable_streams))
>>> - return v4l2_subdev_enable_streams_fallback(sd, pad,
>>> - streams_mask);
>>> + use_s_stream = !v4l2_subdev_has_op(sd, pad, enable_streams);
>>> - state = v4l2_subdev_lock_and_get_active_state(sd);
>>> + if (!use_s_stream)
>>> + state = v4l2_subdev_lock_and_get_active_state(sd);
>>> + else
>>> + state = NULL;
>>> /*
>>> * Verify that the requested streams exist and that they are not
>>> @@ -2231,9 +2213,18 @@ int v4l2_subdev_enable_streams(struct
>>> v4l2_subdev *sd, u32 pad,
>>> already_streaming = v4l2_subdev_is_streaming(sd);
>>> - /* Call the .enable_streams() operation. */
>>> - ret = v4l2_subdev_call(sd, pad, enable_streams, state, pad,
>>> - streams_mask);
>>> + if (!use_s_stream) {
>>> + /* Call the .enable_streams() operation. */
>>> + ret = v4l2_subdev_call(sd, pad, enable_streams, state, pad,
>>> + streams_mask);
>>> + } else {
>>> + /* Start streaming when the first pad is enabled. */
>>> + if (!already_streaming)
>>> + ret = v4l2_subdev_call(sd, video, s_stream, 1);
>>> + else
>>> + ret = 0;
>>> + }
>>> +
>>> if (ret) {
>>> dev_dbg(dev, "enable streams %u:%#llx failed: %d\n", pad,
>>> streams_mask, ret);
>>> @@ -2243,34 +2234,32 @@ int v4l2_subdev_enable_streams(struct
>>> v4l2_subdev *sd, u32 pad,
>>> /* Mark the streams as enabled. */
>>> v4l2_subdev_set_streams_enabled(sd, state, pad, streams_mask,
>>> true);
>>> - if (!already_streaming)
>>> + if (!use_s_stream && !already_streaming)
>>> v4l2_subdev_enable_privacy_led(sd);
>>> done:
>>> - v4l2_subdev_unlock_state(state);
>>> + if (!use_s_stream)
>>> + v4l2_subdev_unlock_state(state);
>>> return ret;
>>> }
>>> EXPORT_SYMBOL_GPL(v4l2_subdev_enable_streams);
>>> -static int v4l2_subdev_disable_streams_fallback(struct v4l2_subdev
>>> *sd, u32 pad,
>>> - u64 streams_mask)
>>> +int v4l2_subdev_disable_streams(struct v4l2_subdev *sd, u32 pad,
>>> + u64 streams_mask)
>>> {
>>> struct device *dev = sd->entity.graph_obj.mdev->dev;
>>> + struct v4l2_subdev_state *state;
>>> + u64 enabled_streams;
>>> + u64 found_streams;
>>> + bool use_s_stream;
>>> int ret;
>>> - /*
>>> - * If the subdev doesn't implement pad-based stream enable,
>>> fall back
>>> - * to the .s_stream() operation.
>>> - */
>>> - if (!(sd->entity.pads[pad].flags & MEDIA_PAD_FL_SOURCE))
>>> - return -EOPNOTSUPP;
>>> + /* A few basic sanity checks first. */
>>> + if (pad >= sd->entity.num_pads)
>>> + return -EINVAL;
>>> - /*
>>> - * .s_stream() means there is no streams support, so only
>>> allowed stream
>>> - * is the implicit stream 0.
>>> - */
>>> - if (streams_mask != BIT_ULL(0))
>>> + if (!(sd->entity.pads[pad].flags & MEDIA_PAD_FL_SOURCE))
>>> return -EOPNOTSUPP;
>>> /*
>>> @@ -2280,46 +2269,16 @@ static int
>>> v4l2_subdev_disable_streams_fallback(struct v4l2_subdev *sd, u32 pad,
>>> if (pad >= sizeof(sd->enabled_pads) * BITS_PER_BYTE)
>>> return -EOPNOTSUPP;
>>> - if (!(sd->enabled_pads & BIT_ULL(pad))) {
>>> - dev_dbg(dev, "pad %u already disabled on %s\n",
>>> - pad, sd->entity.name);
>>> - return -EALREADY;
>>> - }
>>> -
>>> - /* Stop streaming when the last streams are disabled. */
>>> - if (!(sd->enabled_pads & ~BIT_ULL(pad))) {
>>> - ret = v4l2_subdev_call(sd, video, s_stream, 0);
>>> - if (ret)
>>> - return ret;
>>> - }
>>> -
>>> - sd->enabled_pads &= ~BIT_ULL(pad);
>>> -
>>> - return 0;
>>> -}
>>> -
>>> -int v4l2_subdev_disable_streams(struct v4l2_subdev *sd, u32 pad,
>>> - u64 streams_mask)
>>> -{
>>> - struct device *dev = sd->entity.graph_obj.mdev->dev;
>>> - struct v4l2_subdev_state *state;
>>> - u64 enabled_streams;
>>> - u64 found_streams;
>>> - int ret;
>>> -
>>> - /* A few basic sanity checks first. */
>>> - if (pad >= sd->entity.num_pads)
>>> - return -EINVAL;
>>> -
>>> if (!streams_mask)
>>> return 0;
>>> /* Fallback on .s_stream() if .disable_streams() isn't
>>> available. */
>>> - if (!v4l2_subdev_has_op(sd, pad, disable_streams))
>>> - return v4l2_subdev_disable_streams_fallback(sd, pad,
>>> - streams_mask);
>>> + use_s_stream = !v4l2_subdev_has_op(sd, pad, disable_streams);
>>> - state = v4l2_subdev_lock_and_get_active_state(sd);
>>> + if (!use_s_stream)
>>> + state = v4l2_subdev_lock_and_get_active_state(sd);
>>> + else
>>> + state = NULL;
>>> /*
>>> * Verify that the requested streams exist and that they are not
>>> @@ -2345,9 +2304,19 @@ int v4l2_subdev_disable_streams(struct
>>> v4l2_subdev *sd, u32 pad,
>>> dev_dbg(dev, "disable streams %u:%#llx\n", pad, streams_mask);
>>> - /* Call the .disable_streams() operation. */
>>> - ret = v4l2_subdev_call(sd, pad, disable_streams, state, pad,
>>> - streams_mask);
>>> + if (!use_s_stream) {
>>> + /* Call the .disable_streams() operation. */
>>> + ret = v4l2_subdev_call(sd, pad, disable_streams, state, pad,
>>> + streams_mask);
>>> + } else {
>>> + /* Stop streaming when the last streams are disabled. */
>>> +
>>> + if (!(sd->enabled_pads & ~BIT_ULL(pad)))
>>> + ret = v4l2_subdev_call(sd, video, s_stream, 0);
>>> + else
>>> + ret = 0;
>>> + }
>>> +
>>> if (ret) {
>>> dev_dbg(dev, "disable streams %u:%#llx failed: %d\n", pad,
>>> streams_mask, ret);
>>> @@ -2357,10 +2326,12 @@ int v4l2_subdev_disable_streams(struct
>>> v4l2_subdev *sd, u32 pad,
>>> v4l2_subdev_set_streams_enabled(sd, state, pad, streams_mask,
>>> false);
>>> done:
>>> - if (!v4l2_subdev_is_streaming(sd))
>>> - v4l2_subdev_disable_privacy_led(sd);
>>> + if (!use_s_stream) {
>>> + if (!v4l2_subdev_is_streaming(sd))
>>> + v4l2_subdev_disable_privacy_led(sd);
>>> - v4l2_subdev_unlock_state(state);
>>> + v4l2_subdev_unlock_state(state);
>>> + }
>>> return ret;
>>> }
>>>
>>
>
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