linux-kernel - [PATCH 9/9] media: uvcvideo: Support granular power saving for compat syscalls

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Message-Id: <20250528-uvc-grannular-invert-v1-9-d01581f9cc25@chromium.org>
Date: Wed, 28 May 2025 17:58:04 +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>, 
 Hans Verkuil <hverkuil@...all.nl>
Cc: linux-media@...r.kernel.org, linux-kernel@...r.kernel.org, 
 Ricardo Ribalda <ribalda@...omium.org>
Subject: [PATCH 9/9] media: uvcvideo: Support granular power saving for
 compat syscalls

Right now we cannot support granular power saving on compat syscalls
because the VIDIOC_*32 NRs defines are not accessible to drivers.

Use the video_translate_cmd() helper to convert the compat syscall NRs
into syscall NRs.

Signed-off-by: Ricardo Ribalda <ribalda@...omium.org>
---
 drivers/media/usb/uvc/uvc_v4l2.c     | 9 ++-------
 drivers/media/v4l2-core/v4l2-ioctl.c | 3 ++-
 include/media/v4l2-ioctl.h           | 1 +
 3 files changed, 5 insertions(+), 8 deletions(-)

diff --git a/drivers/media/usb/uvc/uvc_v4l2.c b/drivers/media/usb/uvc/uvc_v4l2.c
index fcb1b79c214849ce4da96a86a688d777b32cc688..048ee7e01808c8944f9bd46e5df2931b9c146ad5 100644
--- a/drivers/media/usb/uvc/uvc_v4l2.c
+++ b/drivers/media/usb/uvc/uvc_v4l2.c
@@ -1282,15 +1282,10 @@ static long uvc_v4l2_pm_ioctl(struct file *file,
 static long uvc_v4l2_unlocked_ioctl(struct file *file,
 				    unsigned int cmd, unsigned long arg)
 {
-	/*
-	 * For now, we do not support granular power saving for compat
-	 * syscalls.
-	 */
-	if (in_compat_syscall())
-		return uvc_v4l2_pm_ioctl(file, cmd, arg);
+	unsigned int converted_cmd = video_translate_cmd(cmd);
 
 	/* The following IOCTLs do need to turn on the camera. */
-	switch (cmd) {
+	switch (converted_cmd) {
 	case UVCIOC_CTRL_QUERY:
 	case VIDIOC_G_CTRL:
 	case VIDIOC_G_EXT_CTRLS:
diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
index 650dc1956f73d2f1943b56c42140c7b8d757259f..6fbd28f911cf23eec43ef1adcf64bd46ef067c81 100644
--- a/drivers/media/v4l2-core/v4l2-ioctl.c
+++ b/drivers/media/v4l2-core/v4l2-ioctl.c
@@ -3245,7 +3245,7 @@ static int check_array_args(unsigned int cmd, void *parg, size_t *array_size,
 	return ret;
 }
 
-static unsigned int video_translate_cmd(unsigned int cmd)
+unsigned int video_translate_cmd(unsigned int cmd)
 {
 #if !defined(CONFIG_64BIT) && defined(CONFIG_COMPAT_32BIT_TIME)
 	switch (cmd) {
@@ -3266,6 +3266,7 @@ static unsigned int video_translate_cmd(unsigned int cmd)
 
 	return cmd;
 }
+EXPORT_SYMBOL(video_translate_cmd);
 
 static int video_get_user(void __user *arg, void *parg,
 			  unsigned int real_cmd, unsigned int cmd,
diff --git a/include/media/v4l2-ioctl.h b/include/media/v4l2-ioctl.h
index c6ec87e88dfef9e6cfe1d1fb587c1600882fb14d..437b9f90714c62e0ba434ce47391ef64d88110aa 100644
--- a/include/media/v4l2-ioctl.h
+++ b/include/media/v4l2-ioctl.h
@@ -687,6 +687,7 @@ int v4l2_compat_get_array_args(struct file *file, void *mbuf,
 int v4l2_compat_put_array_args(struct file *file, void __user *user_ptr,
 			       void *mbuf, size_t array_size,
 			       unsigned int cmd, void *arg);
+unsigned int video_translate_cmd(unsigned int cmd);
 
 /**
  * typedef v4l2_kioctl - Typedef used to pass an ioctl handler.

-- 
2.49.0.1266.g31b7d2e469-goog