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Message-ID: <72940e89-0384-4fd3-8a10-42d6db44fdf0@ideasonboard.com>
Date: Thu, 11 Apr 2024 14:07:34 +0300
From: Tomi Valkeinen <tomi.valkeinen@...asonboard.com>
To: Umang Jain <umang.jain@...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()
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(),
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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