linux-kernel - [PATCH 0/9] media: uvcvideo: Implement Granular Power Saving

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Message-Id: <20241126-uvc-granpower-ng-v1-0-6312bf26549c@chromium.org>
Date: Tue, 26 Nov 2024 16:18:50 +0000
From: Ricardo Ribalda <ribalda@...omium.org>
To: Laurent Pinchart <laurent.pinchart@...asonboard.com>, 
 Hans de Goede <hdegoede@...hat.com>, 
 Mauro Carvalho Chehab <mchehab@...nel.org>, 
 Guennadi Liakhovetski <guennadi.liakhovetski@...el.com>
Cc: linux-media@...r.kernel.org, linux-kernel@...r.kernel.org, 
 Mauro Carvalho Chehab <mchehab+samsung@...nel.org>, 
 Ricardo Ribalda <ribalda@...omium.org>, stable@...r.kernel.org
Subject: [PATCH 0/9] media: uvcvideo: Implement Granular Power Saving

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.

While developing this patchset, two bugs were found. The patchset has
been developed so these fixes can be taken independently.

Signed-off-by: Ricardo Ribalda <ribalda@...omium.org>
---
Ricardo Ribalda (9):
      media: uvcvideo: Do not set an async control owned by other fh
      media: uvcvideo: Remove dangling pointers
      media: uvcvideo: Keep streaming state in the file handle
      media: uvcvideo: Move usb_autopm_(get|put)_interface to status_get
      media: uvcvideo: Add a uvc_status guard
      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
      media: uvcvideo: Remove duplicated cap/out code

 drivers/media/usb/uvc/uvc_ctrl.c   |  52 +++++++++-
 drivers/media/usb/uvc/uvc_status.c |  38 +++++++-
 drivers/media/usb/uvc/uvc_v4l2.c   | 190 +++++++++++++++----------------------
 drivers/media/usb/uvc/uvcvideo.h   |   6 ++
 4 files changed, 166 insertions(+), 120 deletions(-)
---
base-commit: 72ad4ff638047bbbdf3232178fea4bec1f429319
change-id: 20241126-uvc-granpower-ng-069185a6d474

Best regards,
-- 
Ricardo Ribalda <ribalda@...omium.org>