Re: [PATCH v3 9/9] media: subdev: Support single-stream case in v4l2_subdev_enable/disable_streams()
From: Tomi Valkeinen
Date: Thu Apr 11 2024 - 07:07:51 EST
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@xxxxxxxxxxxxxxxx/
- 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@xxxxxxxxxxxxxxxx>
---
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;
}