[PATCH v6 0/5] media: uvcvideo: Implement Granular Power Saving

[Ricardo Ribalda]

Right now we power-up the device when a user open() the device and we
power it off when the last user close() the first video node.

This behaviour affects the power consumption of the device is multiple
use cases, such as:
- Polling the privacy gpio
- udev probing the device

This patchset introduces a more granular power saving behaviour where
the camera is only awaken when needed. It is compatible with
asynchronous controls.

Signed-off-by: Ricardo Ribalda <ribalda@xxxxxxxxxxxx>
---
Changes in v6:
- Improve error handling
- Use __free instead of guards()
- Rename uvc_v4l2_unlocked_ioctl
- Link to v5: https://lore.kernel.org/r/20250303-uvc-granpower-ng-v5-0-a3dfbe29fe91@xxxxxxxxxxxx

Changes in v5:
- Improve "media: uvcvideo: Make power management granular" commit
  message.
- Link to v4: https://lore.kernel.org/r/20250226-uvc-granpower-ng-v4-0-3ec9be906048@xxxxxxxxxxxx

Changes in v4:
- CodeStyle
- Create uvc_pm_ functions
- Link to v3: https://lore.kernel.org/r/20250206-uvc-granpower-ng-v3-0-32d0d7b0c5d8@xxxxxxxxxxxx

Changes in v3:
- Fix build error on sh4.
- Link to v2: https://lore.kernel.org/r/20250203-uvc-granpower-ng-v2-0-bef4b55e7b67@xxxxxxxxxxxx

Changes in v2:
- Add missing semicolon.
- Rebase on top of media-committers/next
- Link to v1: https://lore.kernel.org/r/20241126-uvc-granpower-ng-v1-0-6312bf26549c@xxxxxxxxxxxx

---
Ricardo Ribalda (5):
      media: uvcvideo: Keep streaming state in the file handle
      media: uvcvideo: Create uvc_pm_(get|put) functions
      media: uvcvideo: Increase/decrease the PM counter per IOCTL
      media: uvcvideo: Make power management granular
      media: uvcvideo: Do not turn on the camera for some ioctls

 drivers/media/usb/uvc/uvc_ctrl.c |  37 +++++++++----
 drivers/media/usb/uvc/uvc_v4l2.c | 115 +++++++++++++++++++++++++++++++--------
 drivers/media/usb/uvc/uvcvideo.h |   5 ++
 3 files changed, 123 insertions(+), 34 deletions(-)
---
base-commit: f2151613e040973c868d28c8b00885dfab69eb75
change-id: 20241126-uvc-granpower-ng-069185a6d474

Best regards,
-- 
Ricardo Ribalda <ribalda@xxxxxxxxxxxx>