Re: [PATCH v2 3/7] media: uvcvideo: Implement mask for V4L2_CTRL_TYPE_MENU

From: Laurent Pinchart
Date: Fri Jan 06 2023 - 15:23:46 EST

Next message: Bjorn Andersson: "Re: [PATCH v2] soc: qcom: apr: make remove callback of apr driver void returned"
Previous message: William Zhang: "[PATCH 06/16] spi: bcm63xx-hsspi: Endianness fix for ARM based SoC"
In reply to: Ricardo Ribalda: "[PATCH v2 3/7] media: uvcvideo: Implement mask for V4L2_CTRL_TYPE_MENU"
Next in thread: Ricardo Ribalda: "[PATCH v2 6/7] media: uvcvideo: Fix power line control for Lenovo Integrated Camera"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]

Hi Ricardo,

Thank you for the patch.

On Thu, Jan 05, 2023 at 02:52:54PM +0100, Ricardo Ribalda wrote:
> Replace the count with a mask field that lets us choose not only the max
> value, but also the minimum value and what values are valid in between.
>
> Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> Signed-off-by: Ricardo Ribalda <ribalda@xxxxxxxxxxxx>
> Suggested-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> ---
> drivers/media/usb/uvc/uvc_ctrl.c | 33 +++++++++++++++++++++++----------
> drivers/media/usb/uvc/uvc_driver.c | 4 +++-
> drivers/media/usb/uvc/uvc_v4l2.c | 3 ++-
> drivers/media/usb/uvc/uvcvideo.h | 2 +-
> 4 files changed, 29 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c
> index ffa0e2654264..2ebe5cc18ad9 100644
> --- a/drivers/media/usb/uvc/uvc_ctrl.c
> +++ b/drivers/media/usb/uvc/uvc_ctrl.c
> @@ -6,6 +6,7 @@
> * Laurent Pinchart (laurent.pinchart@xxxxxxxxxxxxxxxx)
> */
>
> +#include <linux/bitops.h>
> #include <linux/kernel.h>
> #include <linux/list.h>
> #include <linux/module.h>
> @@ -525,7 +526,8 @@ static const struct uvc_control_mapping uvc_ctrl_mappings[] = {
> .v4l2_type = V4L2_CTRL_TYPE_MENU,
> .data_type = UVC_CTRL_DATA_TYPE_BITMASK,
> .menu_info = exposure_auto_controls,
> - .menu_count = ARRAY_SIZE(exposure_auto_controls),
> + .menu_mask =
> + GENMASK(ARRAY_SIZE(exposure_auto_controls) - 1, 0),

To be consistent, could this be

.menu_mask = GENMASK(V4L2_EXPOSURE_APERTURE_PRIORITY,
V4L2_EXPOSURE_AUTO),

? I can fix this when applying.

> .slave_ids = { V4L2_CID_EXPOSURE_ABSOLUTE, },
> },
> {
> @@ -731,7 +733,8 @@ static const struct uvc_control_mapping uvc_ctrl_mappings_uvc11[] = {
> .v4l2_type = V4L2_CTRL_TYPE_MENU,
> .data_type = UVC_CTRL_DATA_TYPE_ENUM,
> .menu_info = power_line_frequency_controls,
> - .menu_count = ARRAY_SIZE(power_line_frequency_controls) - 1,
> + .menu_mask = GENMASK(V4L2_CID_POWER_LINE_FREQUENCY_60HZ,
> + V4L2_CID_POWER_LINE_FREQUENCY_DISABLED),
> },
> };
>
> @@ -745,7 +748,8 @@ static const struct uvc_control_mapping uvc_ctrl_mappings_uvc15[] = {
> .v4l2_type = V4L2_CTRL_TYPE_MENU,
> .data_type = UVC_CTRL_DATA_TYPE_ENUM,
> .menu_info = power_line_frequency_controls,
> - .menu_count = ARRAY_SIZE(power_line_frequency_controls),
> + .menu_mask = GENMASK(V4L2_CID_POWER_LINE_FREQUENCY_AUTO,
> + V4L2_CID_POWER_LINE_FREQUENCY_DISABLED),
> },
> };
>
> @@ -975,7 +979,9 @@ static s32 __uvc_ctrl_get_value(struct uvc_control_mapping *mapping,
> const struct uvc_menu_info *menu = mapping->menu_info;
> unsigned int i;
>
> - for (i = 0; i < mapping->menu_count; ++i, ++menu) {
> + for (i = 0; BIT(i) <= mapping->menu_mask; ++i, ++menu) {
> + if (!test_bit(i, &mapping->menu_mask))
> + continue;

Now that I re-read this, I think there is a problem (update: after
writing this long explanation, the problem isn't in this patch, but I'll
keep the text below for reference).

This function translates a UVC control value to a V4L2 control value.
'i' is the V4L2 control value, as shown two lines down by

value = i;

that makes the function return 'i' (we could just return i here). You're
testing if bit i is set in menu_mask, menu_mask is thus a bitmask of
supported V4L2 control values. That's fine for the controls listed
above, but below you have, in the definition of
uvc_ctrl_power_line_mapping_limited,

.menu_mask =
GENMASK(ARRAY_SIZE(power_line_frequency_controls_limited) - 1, 0),

with

static const struct uvc_menu_info power_line_frequency_controls_limited[] = {
{ 1, "50 Hz" },
{ 2, "60 Hz" },
};

V4L2 defines

enum v4l2_power_line_frequency {
V4L2_CID_POWER_LINE_FREQUENCY_DISABLED = 0,
V4L2_CID_POWER_LINE_FREQUENCY_50HZ = 1,
V4L2_CID_POWER_LINE_FREQUENCY_60HZ = 2,
V4L2_CID_POWER_LINE_FREQUENCY_AUTO = 3,
};

so the above is effectively GENMASK(V4L2_CID_POWER_LINE_FREQUENCY_50HZ,
V4L2_CID_POWER_LINE_FREQUENCY_DISABLED) and that's not correct.

We can just use GENMASK(V4L2_CID_POWER_LINE_FREQUENCY_60HZ,
V4L2_CID_POWER_LINE_FREQUENCY_50HZ) here, as the index 'i' in various
loops is also used to index the menu_info array.

This problem was introduced by commit 382075604a68 ("media: uvcvideo:
Limit power line control for Quanta UVC Webcam") which broke the
assumption that the menu_info array indices matched the standard V4L2
Amenu values, it is thus not a regression in this patch. I'll comment in
further patches in this series on related code, maybe it gets fixed
somewhere :-)

> if (menu->value == value) {
> value = i;
> break;
> @@ -1228,12 +1234,14 @@ static int __uvc_query_v4l2_ctrl(struct uvc_video_chain *chain,
>
> switch (mapping->v4l2_type) {
> case V4L2_CTRL_TYPE_MENU:
> - v4l2_ctrl->minimum = 0;
> - v4l2_ctrl->maximum = mapping->menu_count - 1;
> + v4l2_ctrl->minimum = ffs(mapping->menu_mask) - 1;
> + v4l2_ctrl->maximum = fls(mapping->menu_mask) - 1;
> v4l2_ctrl->step = 1;
>
> menu = mapping->menu_info;
> - for (i = 0; i < mapping->menu_count; ++i, ++menu) {
> + for (i = 0; BIT(i) <= mapping->menu_mask; ++i, ++menu) {
> + if (!test_bit(i, &mapping->menu_mask))
> + continue;
> if (menu->value == v4l2_ctrl->default_value) {
> v4l2_ctrl->default_value = i;
> break;
> @@ -1354,7 +1362,7 @@ int uvc_query_v4l2_menu(struct uvc_video_chain *chain,
> goto done;
> }
>
> - if (query_menu->index >= mapping->menu_count) {
> + if (!test_bit(query_menu->index, &mapping->menu_mask)) {
> ret = -EINVAL;
> goto done;
> }
> @@ -1868,8 +1876,13 @@ int uvc_ctrl_set(struct uvc_fh *handle,
> break;
>
> case V4L2_CTRL_TYPE_MENU:
> - if (xctrl->value < 0 || xctrl->value >= mapping->menu_count)
> + if (xctrl->value < (ffs(mapping->menu_mask) - 1) ||
> + xctrl->value > (fls(mapping->menu_mask) - 1))
> return -ERANGE;
> +
> + if (!test_bit(xctrl->value, &mapping->menu_mask))
> + return -EINVAL;
> +
> value = mapping->menu_info[xctrl->value].value;
>
> /*
> @@ -2306,7 +2319,7 @@ static int __uvc_ctrl_add_mapping(struct uvc_video_chain *chain,
>
> INIT_LIST_HEAD(&map->ev_subs);
>
> - size = sizeof(*mapping->menu_info) * mapping->menu_count;
> + size = sizeof(*mapping->menu_info) * fls(mapping->menu_mask);
> map->menu_info = kmemdup(mapping->menu_info, size, GFP_KERNEL);
> if (!map->menu_info)
> goto err_nomem;
> diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c
> index 6d08457ecb9c..e659670ea2d8 100644
> --- a/drivers/media/usb/uvc/uvc_driver.c
> +++ b/drivers/media/usb/uvc/uvc_driver.c
> @@ -7,6 +7,7 @@
> */
>
> #include <linux/atomic.h>
> +#include <linux/bits.h>
> #include <linux/gpio/consumer.h>
> #include <linux/kernel.h>
> #include <linux/list.h>
> @@ -2391,7 +2392,8 @@ static const struct uvc_control_mapping uvc_ctrl_power_line_mapping_limited = {
> .v4l2_type = V4L2_CTRL_TYPE_MENU,
> .data_type = UVC_CTRL_DATA_TYPE_ENUM,
> .menu_info = power_line_frequency_controls_limited,
> - .menu_count = ARRAY_SIZE(power_line_frequency_controls_limited),
> + .menu_mask =
> + GENMASK(ARRAY_SIZE(power_line_frequency_controls_limited) - 1, 0),
> };
>
> static const struct uvc_device_info uvc_ctrl_power_line_limited = {
> diff --git a/drivers/media/usb/uvc/uvc_v4l2.c b/drivers/media/usb/uvc/uvc_v4l2.c
> index 3edb54c086b2..0774a11360c0 100644
> --- a/drivers/media/usb/uvc/uvc_v4l2.c
> +++ b/drivers/media/usb/uvc/uvc_v4l2.c
> @@ -6,6 +6,7 @@
> * Laurent Pinchart (laurent.pinchart@xxxxxxxxxxxxxxxx)
> */
>
> +#include <linux/bits.h>
> #include <linux/compat.h>
> #include <linux/kernel.h>
> #include <linux/list.h>
> @@ -80,7 +81,7 @@ static int uvc_ioctl_ctrl_map(struct uvc_video_chain *chain,
> goto free_map;
> }
>
> - map->menu_count = xmap->menu_count;
> + map->menu_mask = GENMASK(xmap->menu_count - 1, 0);
> break;
>
> default:
> diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h
> index 41ba0bbd8171..a8eec43cd860 100644
> --- a/drivers/media/usb/uvc/uvcvideo.h
> +++ b/drivers/media/usb/uvc/uvcvideo.h
> @@ -115,7 +115,7 @@ struct uvc_control_mapping {
> u32 data_type;
>
> const struct uvc_menu_info *menu_info;
> - u32 menu_count;
> + unsigned long menu_mask;
>
> u32 master_id;
> s32 master_manual;

--
Regards,

Laurent Pinchart

Next message: Bjorn Andersson: "Re: [PATCH v2] soc: qcom: apr: make remove callback of apr driver void returned"
Previous message: William Zhang: "[PATCH 06/16] spi: bcm63xx-hsspi: Endianness fix for ARM based SoC"
In reply to: Ricardo Ribalda: "[PATCH v2 3/7] media: uvcvideo: Implement mask for V4L2_CTRL_TYPE_MENU"
Next in thread: Ricardo Ribalda: "[PATCH v2 6/7] media: uvcvideo: Fix power line control for Lenovo Integrated Camera"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]