mbox series

[v3,0/7,RESEND] media: uvcvideo: Implement granular power management

Message ID 20220920-resend-powersave-v3-0-c47856d8757e@chromium.org
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Series media: uvcvideo: Implement granular power management | expand

Message

Ricardo Ribalda Oct. 26, 2022, 12:06 p.m. UTC 
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.

And now that all the access to the hardware, has a common entry path,
use it to fix the race conditions to hardware disconnects.

To: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: linux-media@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Tomasz Figa <tfiga@chromium.org>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Max Staudt <mstaudt@chromium.org>
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
---
Changes in v3:
- Rebase on top of uvc/next
- Reorder series, and put "controversial" patches at the end.
- Fix "use-before-set" bug. Thanks Max!
- Link to v2: https://lore.kernel.org/r/20220920-resend-powersave-v2-0-5135d1bb1c38@chromium.org

Changes in v2:
- Make access to uvc_status contitional
- Merge with Guenter race condition patchset: https://lore.kernel.org/lkml/20200917022547.198090-1-linux@roeck-us.net/
- Link to v1: https://lore.kernel.org/r/20220920-resend-powersave-v1-0-123aa2ba3836@chromium.org

---
Guenter Roeck (4):
      media: uvcvideo: Cancel async worker earlier
      media: uvcvideo: Release stream queue when unregistering video device
      media: uvcvideo: Lock video streams and queues while unregistering
      media: uvcvideo: Protect uvc queue file operations against disconnect

Ricardo Ribalda (3):
      media: uvcvideo: Refactor streamon/streamoff
      media: uvcvideo: Do power management granularly
      media: uvcvideo: Only call status ep if hw supports it

 drivers/media/usb/uvc/uvc_ctrl.c   |  11 +-
 drivers/media/usb/uvc/uvc_driver.c |  35 +++++--
 drivers/media/usb/uvc/uvc_queue.c  |  32 +++++-
 drivers/media/usb/uvc/uvc_status.c |  11 +-
 drivers/media/usb/uvc/uvc_v4l2.c   | 206 ++++++++++++++++++++++++++++++-------
 drivers/media/usb/uvc/uvcvideo.h   |   2 +
 6 files changed, 248 insertions(+), 49 deletions(-)
---
base-commit: 58540610e464d8b2ba46a11b81c3e6fcc4118fae
change-id: 20220920-resend-powersave-5981719ed267

Best regards,

Comments

Max Staudt Oct. 27, 2022, 8:45 a.m. UTC | #1 
Thanks Ricardo!


I've reviewed v2 for locking issues etc., albeit without much background 
on V4L, UVC, USB yet.

If this is good enough, then please have a

Reviewed-by: Max Staudt <mstaudt@chromium.org>