[PATCH v4 2/2] media: uvcvideo: Do power management granularly

From: Ricardo Ribalda
Date: Fri Dec 02 2022 - 12:19:58 EST

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Previous message: Ricardo Ribalda: "[PATCH v4 1/2] media: uvcvideo: Refactor streamon/streamoff"
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Instead of suspending/resume the USB device at open()/close(), do it
when the device is actually used.

This way we can reduce the power consumption when a service is holding
the video device and leaving it in an idle state.

Reviewed-by: Tomasz Figa <tfiga@xxxxxxxxxxxx>
Reviewed-by: Max Staudt <mstaudt@xxxxxxxxxxxx>
Signed-off-by: Ricardo Ribalda <ribalda@xxxxxxxxxxxx>
---
drivers/media/usb/uvc/uvc_v4l2.c | 174 ++++++++++++++++++++++++++++++++-------
1 file changed, 142 insertions(+), 32 deletions(-)

diff --git a/drivers/media/usb/uvc/uvc_v4l2.c b/drivers/media/usb/uvc/uvc_v4l2.c
index 1389a87b8ae1..f5b0f1905962 100644
--- a/drivers/media/usb/uvc/uvc_v4l2.c
+++ b/drivers/media/usb/uvc/uvc_v4l2.c
@@ -25,6 +25,46 @@

#include "uvcvideo.h"

+/* ------------------------------------------------------------------------
+ * UVC power management
+ */
+
+static int uvc_pm_get(struct uvc_streaming *stream)
+{
+ int ret;
+
+ ret = usb_autopm_get_interface(stream->dev->intf);
+ if (ret)
+ return ret;
+
+ mutex_lock(&stream->dev->lock);
+ if (!stream->dev->users)
+ ret = uvc_status_start(stream->dev, GFP_KERNEL);
+ if (!ret)
+ stream->dev->users++;
+ mutex_unlock(&stream->dev->lock);
+
+ if (ret)
+ usb_autopm_put_interface(stream->dev->intf);
+
+ return ret;
+}
+
+static void uvc_pm_put(struct uvc_streaming *stream)
+{
+ mutex_lock(&stream->dev->lock);
+ if (WARN_ON(!stream->dev->users)) {
+ mutex_unlock(&stream->dev->lock);
+ return;
+ }
+ stream->dev->users--;
+ if (!stream->dev->users)
+ uvc_status_stop(stream->dev);
+ mutex_unlock(&stream->dev->lock);
+
+ usb_autopm_put_interface(stream->dev->intf);
+}
+
/* ------------------------------------------------------------------------
* UVC ioctls
*/
@@ -249,6 +289,9 @@ static int uvc_v4l2_try_format(struct uvc_streaming *stream,
* developers test their webcams with the Linux driver as well as with
* the Windows driver).
*/
+ ret = uvc_pm_get(stream);
+ if (ret)
+ return ret;
mutex_lock(&stream->mutex);
if (stream->dev->quirks & UVC_QUIRK_PROBE_EXTRAFIELDS)
probe->dwMaxVideoFrameSize =
@@ -257,6 +300,7 @@ static int uvc_v4l2_try_format(struct uvc_streaming *stream,
/* Probe the device. */
ret = uvc_probe_video(stream, probe);
mutex_unlock(&stream->mutex);
+ uvc_pm_put(stream);
if (ret < 0)
return ret;

@@ -468,7 +512,13 @@ static int uvc_v4l2_set_streamparm(struct uvc_streaming *stream,
}

/* Probe the device with the new settings. */
+ ret = uvc_pm_get(stream);
+ if (ret) {
+ mutex_unlock(&stream->mutex);
+ return ret;
+ }
ret = uvc_probe_video(stream, &probe);
+ uvc_pm_put(stream);
if (ret < 0) {
mutex_unlock(&stream->mutex);
return ret;
@@ -559,36 +609,29 @@ static int uvc_v4l2_open(struct file *file)
{
struct uvc_streaming *stream;
struct uvc_fh *handle;
- int ret = 0;

stream = video_drvdata(file);
uvc_dbg(stream->dev, CALLS, "%s\n", __func__);

- ret = usb_autopm_get_interface(stream->dev->intf);
- if (ret < 0)
- return ret;
-
/* Create the device handle. */
handle = kzalloc(sizeof(*handle), GFP_KERNEL);
- if (handle == NULL) {
- usb_autopm_put_interface(stream->dev->intf);
+ if (!handle)
return -ENOMEM;
- }

- mutex_lock(&stream->dev->lock);
- if (stream->dev->users == 0) {
- ret = uvc_status_start(stream->dev, GFP_KERNEL);
- if (ret < 0) {
- mutex_unlock(&stream->dev->lock);
- usb_autopm_put_interface(stream->dev->intf);
+ /*
+ * If the uvc evdev exists we cannot suspend when the device
+ * is idle. Otherwise we will miss button actions.
+ */
+ if (stream->dev->input) {
+ int ret;
+
+ ret = uvc_pm_get(stream);
+ if (ret) {
kfree(handle);
return ret;
}
}

- stream->dev->users++;
- mutex_unlock(&stream->dev->lock);
-
v4l2_fh_init(&handle->vfh, &stream->vdev);
v4l2_fh_add(&handle->vfh);
handle->chain = stream->chain;
@@ -610,6 +653,12 @@ static int uvc_v4l2_release(struct file *file)
if (uvc_has_privileges(handle))
uvc_queue_release(&stream->queue);

+ if (handle->is_streaming)
+ uvc_pm_put(stream);
+
+ if (stream->dev->input)
+ uvc_pm_put(stream);
+
/* Release the file handle. */
uvc_dismiss_privileges(handle);
v4l2_fh_del(&handle->vfh);
@@ -617,12 +666,6 @@ static int uvc_v4l2_release(struct file *file)
kfree(handle);
file->private_data = NULL;

- mutex_lock(&stream->dev->lock);
- if (--stream->dev->users == 0)
- uvc_status_stop(stream->dev);
- mutex_unlock(&stream->dev->lock);
-
- usb_autopm_put_interface(stream->dev->intf);
return 0;
}

@@ -849,9 +892,17 @@ static int uvc_ioctl_streamon(struct file *file, void *fh,

if (handle->is_streaming)
goto unlock;
+
+ ret = uvc_pm_get(stream);
+ if (ret)
+ goto unlock;
+
ret = uvc_queue_streamon(&stream->queue, type);
handle->is_streaming = !ret;

+ if (!handle->is_streaming)
+ uvc_pm_put(stream);
+
unlock:
mutex_unlock(&stream->mutex);

@@ -875,6 +926,9 @@ static int uvc_ioctl_streamoff(struct file *file, void *fh,
ret = uvc_queue_streamoff(&stream->queue, type);
handle->is_streaming = !!ret;

+ if (!handle->is_streaming)
+ uvc_pm_put(stream);
+
unlock:
mutex_unlock(&stream->mutex);

@@ -928,6 +982,7 @@ static int uvc_ioctl_g_input(struct file *file, void *fh, unsigned int *input)
{
struct uvc_fh *handle = fh;
struct uvc_video_chain *chain = handle->chain;
+ struct uvc_streaming *stream = handle->stream;
u8 *buf;
int ret;

@@ -941,9 +996,16 @@ static int uvc_ioctl_g_input(struct file *file, void *fh, unsigned int *input)
if (!buf)
return -ENOMEM;

+ ret = uvc_pm_get(stream);
+ if (ret) {
+ kfree(buf);
+ return ret;
+ }
+
ret = uvc_query_ctrl(chain->dev, UVC_GET_CUR, chain->selector->id,
chain->dev->intfnum, UVC_SU_INPUT_SELECT_CONTROL,
buf, 1);
+ uvc_pm_put(stream);
if (!ret)
*input = *buf - 1;

@@ -956,6 +1018,7 @@ static int uvc_ioctl_s_input(struct file *file, void *fh, unsigned int input)
{
struct uvc_fh *handle = fh;
struct uvc_video_chain *chain = handle->chain;
+ struct uvc_streaming *stream = handle->stream;
u8 *buf;
int ret;

@@ -977,10 +1040,17 @@ static int uvc_ioctl_s_input(struct file *file, void *fh, unsigned int input)
if (!buf)
return -ENOMEM;

+ ret = uvc_pm_get(stream);
+ if (ret) {
+ kfree(buf);
+ return ret;
+ }
+
*buf = input + 1;
ret = uvc_query_ctrl(chain->dev, UVC_SET_CUR, chain->selector->id,
chain->dev->intfnum, UVC_SU_INPUT_SELECT_CONTROL,
buf, 1);
+ uvc_pm_put(stream);
kfree(buf);

return ret;
@@ -991,8 +1061,15 @@ static int uvc_ioctl_queryctrl(struct file *file, void *fh,
{
struct uvc_fh *handle = fh;
struct uvc_video_chain *chain = handle->chain;
+ struct uvc_streaming *stream = handle->stream;
+ int ret;

- return uvc_query_v4l2_ctrl(chain, qc);
+ ret = uvc_pm_get(stream);
+ if (ret)
+ return ret;
+ ret = uvc_query_v4l2_ctrl(chain, qc);
+ uvc_pm_put(stream);
+ return ret;
}

static int uvc_ioctl_query_ext_ctrl(struct file *file, void *fh,
@@ -1000,10 +1077,15 @@ static int uvc_ioctl_query_ext_ctrl(struct file *file, void *fh,
{
struct uvc_fh *handle = fh;
struct uvc_video_chain *chain = handle->chain;
+ struct uvc_streaming *stream = handle->stream;
struct v4l2_queryctrl qc = { qec->id };
int ret;

+ ret = uvc_pm_get(stream);
+ if (ret)
+ return ret;
ret = uvc_query_v4l2_ctrl(chain, &qc);
+ uvc_pm_put(stream);
if (ret)
return ret;

@@ -1049,6 +1131,7 @@ static int uvc_ioctl_g_ext_ctrls(struct file *file, void *fh,
{
struct uvc_fh *handle = fh;
struct uvc_video_chain *chain = handle->chain;
+ struct uvc_streaming *stream = handle->stream;
struct v4l2_ext_control *ctrl = ctrls->controls;
unsigned int i;
int ret;
@@ -1073,22 +1156,30 @@ static int uvc_ioctl_g_ext_ctrls(struct file *file, void *fh,
return 0;
}

+ ret = uvc_pm_get(stream);
+ if (ret)
+ return ret;
ret = uvc_ctrl_begin(chain);
- if (ret < 0)
+ if (ret < 0) {
+ uvc_pm_put(stream);
return ret;
+ }

for (i = 0; i < ctrls->count; ++ctrl, ++i) {
ret = uvc_ctrl_get(chain, ctrl);
if (ret < 0) {
uvc_ctrl_rollback(handle);
ctrls->error_idx = i;
- return ret;
+ goto done;
}
}

ctrls->error_idx = 0;

- return uvc_ctrl_rollback(handle);
+ ret = uvc_ctrl_rollback(handle);
+done:
+ uvc_pm_put(stream);
+ return ret;
}

static int uvc_ioctl_s_try_ext_ctrls(struct uvc_fh *handle,
@@ -1097,6 +1188,7 @@ static int uvc_ioctl_s_try_ext_ctrls(struct uvc_fh *handle,
{
struct v4l2_ext_control *ctrl = ctrls->controls;
struct uvc_video_chain *chain = handle->chain;
+ struct uvc_streaming *stream = handle->stream;
unsigned int i;
int ret;

@@ -1104,9 +1196,15 @@ static int uvc_ioctl_s_try_ext_ctrls(struct uvc_fh *handle,
if (ret < 0)
return ret;

+ ret = uvc_pm_get(stream);
+ if (ret)
+ return ret;
+
ret = uvc_ctrl_begin(chain);
- if (ret < 0)
+ if (ret < 0) {
+ uvc_pm_put(stream);
return ret;
+ }

for (i = 0; i < ctrls->count; ++ctrl, ++i) {
ret = uvc_ctrl_set(handle, ctrl);
@@ -1114,16 +1212,20 @@ static int uvc_ioctl_s_try_ext_ctrls(struct uvc_fh *handle,
uvc_ctrl_rollback(handle);
ctrls->error_idx = ioctl == VIDIOC_S_EXT_CTRLS ?
ctrls->count : i;
- return ret;
+ goto done;
}
}

ctrls->error_idx = 0;

if (ioctl == VIDIOC_S_EXT_CTRLS)
- return uvc_ctrl_commit(handle, ctrls);
+ ret = uvc_ctrl_commit(handle, ctrls);
else
- return uvc_ctrl_rollback(handle);
+ ret = uvc_ctrl_rollback(handle);
+
+done:
+ uvc_pm_put(stream);
+ return ret;
}

static int uvc_ioctl_s_ext_ctrls(struct file *file, void *fh,
@@ -1147,8 +1249,16 @@ static int uvc_ioctl_querymenu(struct file *file, void *fh,
{
struct uvc_fh *handle = fh;
struct uvc_video_chain *chain = handle->chain;
+ struct uvc_streaming *stream = handle->stream;
+ int ret;
+
+ ret = uvc_pm_get(stream);
+ if (ret)
+ return ret;
+ ret = uvc_query_v4l2_menu(chain, qm);
+ uvc_pm_put(stream);

- return uvc_query_v4l2_menu(chain, qm);
+ return ret;
}

static int uvc_ioctl_g_selection(struct file *file, void *fh,

--
2.39.0.rc0.267.gcb52ba06e7-goog-b4-0.11.0-dev-696ae

Next message: David Hildenbrand: "Re: [PATCH v3 1/2] mm/migrate: Fix read-only page got writable when recover pte"
Previous message: Ricardo Ribalda: "[PATCH v4 1/2] media: uvcvideo: Refactor streamon/streamoff"
In reply to: Sergey Senozhatsky: "Re: [PATCH v4 1/2] media: uvcvideo: Refactor streamon/streamoff"
Next in thread: Sergey Senozhatsky: "Re: [PATCH v4 2/2] media: uvcvideo: Do power management granularly"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]