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[35.245.174.172]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-6dfade72b59sm18434356d6.87.2025.01.11.01.57.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 11 Jan 2025 01:57:23 -0800 (PST) From: Ricardo Ribalda Date: Sat, 11 Jan 2025 09:57:21 +0000 Subject: [PATCH v4] media: uvcvideo: Set V4L2_CTRL_FLAG_DISABLED during queryctrl errors Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20250111-uvc-eaccess-v4-1-c7759bfd1bd4@chromium.org> X-B4-Tracking: v=1; b=H4sIAIFAgmcC/23MQQ6DIBRF0a0YxqUBPqB21H00HegXlIHaQCVtj HsvmjSpjcP3knNnEox3JpBLNhNvogtuHNKQp4xgVw2toa5JmwgmJBcc6BSRmgrRhEBzpRCZ5hV oRpJ4eGPda6vd7ml3LjxH/97ika/vcSdyyqkWhtXSImqQV+z82LupP4++JWsqil9e7rlIvLZaC YZFXejmgMOXK8ZZvueQeFlaAFCN4gB/fFmWD+ZdKKcnAQAA To: Hans Verkuil , Laurent Pinchart , Hans de Goede , Mauro Carvalho Chehab Cc: linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, Ricardo Ribalda X-Mailer: b4 0.13.0 To implement VIDIOC_QUERYCTRL, we need to know the minimum, maximum, step and flags of the control. For some of the controls, this involves querying the actual hardware. Some non-compliant cameras produce errors when we query them. Right now, we populate that error to userspace. When an error happens, the v4l2 framework does not copy the v4l2_queryctrl struct to userspace. Also, userspace apps are not ready to handle any other error than -EINVAL. One of the main usecases of VIDIOC_QUERYCTRL is enumerating the controls of a device. This is done using the V4L2_CTRL_FLAG_NEXT_CTRL flag. In that usecase, a non-compliant control will make it almost impossible to enumerate all controls of the device. A control with an invalid max/min/step/flags is better than non being able to enumerate the rest of the controls. This patch makes VIDIOC_QUERYCTRL return 0 in all the error cases different than -EINVAL, introduces a warning in dmesg so we can have a trace of what has happened and sets the V4L2_CTRL_FLAG_DISABLED. Signed-off-by: Ricardo Ribalda --- Hi 2*Hans and Laurent! I came around a device that was listing just a couple of controls when it should be listing much more. Some debugging latter I found that the device was returning -EIO when all the focal controls were read. Lots of good arguments in favor/against this patch in the v1. Please check! Without this patch: $ v4l2-ctl --list-ctrls auto_exposure 0x009a0901 (menu) : min=3D0 max=3D3 defau= lt=3D3 value=3D3 (Aperture Priority Mode) exposure_time_absolute 0x009a0902 (int) : min=3D50 max=3D10000 = step=3D1 default=3D166 value=3D166 flags=3Dinactive exposure_dynamic_framerate 0x009a0903 (bool) : default=3D0 value=3D0 region_of_interest_auto_control 0x009a1902 (bitmask): max=3D0x00000001 defa= ult=3D0x00000001 value=3D1 With this patch: $ v4l2-ctl --list-ctrls auto_exposure 0x009a0901 (menu) : min=3D0 max=3D3 defau= lt=3D3 value=3D3 (Aperture Priority Mode) exposure_time_absolute 0x009a0902 (int) : min=3D50 max=3D10000 = step=3D1 default=3D166 value=3D166 flags=3Dinactive exposure_dynamic_framerate 0x009a0903 (bool) : default=3D0 value=3D0 error 5 getting ext_ctrl Focus, Absolute error 5 getting ext_ctrl Focus, Automatic Continuous region_of_interest_rectangle 0x009a1901 (unknown): type=3D107 value=3Dun= supported payload type flags=3Dhas-payload region_of_interest_auto_control 0x009a1902 (bitmask): max=3D0x00000001 defa= ult=3D0x00000001 value=3D1 -- --- Changes in v4: - Display control name (Thanks Hans) - Link to v3: https://lore.kernel.org/r/20250107-uvc-eaccess-v3-1-99f3335d5= 133@chromium.org Changes in v3: - Add a retry mechanism during error. - Set V4L2_CTRL_FLAG_DISABLED flag. - Link to v2: https://lore.kernel.org/r/20241219-uvc-eaccess-v2-1-bf6520c8b= 86d@chromium.org Changes in v2: - Never return error, even if we are not enumerating the controls - Improve commit message. - Link to v1: https://lore.kernel.org/r/20241213-uvc-eaccess-v1-1-62e0b4fcc= 634@chromium.org --- drivers/media/usb/uvc/uvc_ctrl.c | 43 ++++++++++++++++++++++++++++++++----= ---- 1 file changed, 35 insertions(+), 8 deletions(-) diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_c= trl.c index 4e58476d305e..9d7812e8572d 100644 --- a/drivers/media/usb/uvc/uvc_ctrl.c +++ b/drivers/media/usb/uvc/uvc_ctrl.c @@ -1280,6 +1280,8 @@ static u32 uvc_get_ctrl_bitmap(struct uvc_control *ct= rl, return ~0; } =20 +#define MAX_QUERY_RETRIES 2 + static int __uvc_query_v4l2_ctrl(struct uvc_video_chain *chain, struct uvc_control *ctrl, struct uvc_control_mapping *mapping, @@ -1305,19 +1307,44 @@ static int __uvc_query_v4l2_ctrl(struct uvc_video_c= hain *chain, __uvc_find_control(ctrl->entity, mapping->master_id, &master_map, &master_ctrl, 0); if (master_ctrl && (master_ctrl->info.flags & UVC_CTRL_FLAG_GET_CUR)) { + unsigned int retries; s32 val; - int ret =3D __uvc_ctrl_get(chain, master_ctrl, master_map, &val); - if (ret < 0) - return ret; + int ret; =20 - if (val !=3D mapping->master_manual) - v4l2_ctrl->flags |=3D V4L2_CTRL_FLAG_INACTIVE; + for (retries =3D 0; retries < MAX_QUERY_RETRIES; retries++) { + ret =3D __uvc_ctrl_get(chain, master_ctrl, master_map, + &val); + if (ret >=3D 0) + break; + } + + if (ret < 0) { + dev_warn_ratelimited(&chain->dev->udev->dev, + "UVC non compliance: Error %d querying master control %x (%s)\n", + ret, master_map->id, + uvc_map_get_name(master_map)); + } else if (val !=3D mapping->master_manual) { + v4l2_ctrl->flags |=3D V4L2_CTRL_FLAG_INACTIVE; + } } =20 if (!ctrl->cached) { - int ret =3D uvc_ctrl_populate_cache(chain, ctrl); - if (ret < 0) - return ret; + unsigned int retries; + int ret; + + for (retries =3D 0; retries < MAX_QUERY_RETRIES; retries++) { + ret =3D uvc_ctrl_populate_cache(chain, ctrl); + if (ret >=3D 0) + break; + } + + if (ret < 0) { + dev_warn_ratelimited(&chain->dev->udev->dev, + "UVC non compliance: Error %d populating cache of control %x (%s= )\n", + ret, mapping->id, + uvc_map_get_name(mapping)); + v4l2_ctrl->flags |=3D V4L2_CTRL_FLAG_DISABLED; + } } =20 if (ctrl->info.flags & UVC_CTRL_FLAG_GET_DEF) { --- base-commit: c5aa327e10b194884a9c9001a751f6e4703bc3e3 change-id: 20241213-uvc-eaccess-755cc061a360 Best regards, --=20 Ricardo Ribalda