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[35.236.236.5]) by smtp.gmail.com with ESMTPSA id ada2fe7eead31-4b2bfad38ecsm230202137.29.2024.12.19.07.33.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 19 Dec 2024 07:33:32 -0800 (PST) From: Ricardo Ribalda Date: Thu, 19 Dec 2024 15:33:29 +0000 Subject: [PATCH v2] media: uvcvideo: Filter hw errors while enumerating controls 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: <20241219-uvc-eaccess-v2-1-bf6520c8b86d@chromium.org> X-B4-Tracking: v=1; b=H4sIAMk8ZGcC/23MOw7CMBBF0a1EU2PkX4xExT5QCjNM4ikSIzuxQ JH3jklNeZ/0zg6ZElOGa7dDosKZ49JCnzrA4JeJBD9bg5baKq2M2AoK8oiUs7j0PaJ0yhsnoT1 eiUZ+H9p9aB04rzF9Dryo3/rfKUoo4TTJhx0RnbE3DCnOvM3nmCYYaq1fRhqSbqkAAAA= 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 and introduces a warning in dmesg so we can have a trace of what has happened. 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 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 | 19 +++++++++++++------ 1 file changed, 13 insertions(+), 6 deletions(-) diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_c= trl.c index 4e58476d305e..43ddc5bb02db 100644 --- a/drivers/media/usb/uvc/uvc_ctrl.c +++ b/drivers/media/usb/uvc/uvc_ctrl.c @@ -1307,17 +1307,24 @@ static int __uvc_query_v4l2_ctrl(struct uvc_video_c= hain *chain, if (master_ctrl && (master_ctrl->info.flags & UVC_CTRL_FLAG_GET_CUR)) { s32 val; int ret =3D __uvc_ctrl_get(chain, master_ctrl, master_map, &val); - if (ret < 0) - return ret; =20 - if (val !=3D mapping->master_manual) - v4l2_ctrl->flags |=3D V4L2_CTRL_FLAG_INACTIVE; + if (ret < 0) { + dev_warn_ratelimited(&chain->dev->udev->dev, + "UVC non compliance: Error %d querying master control %x\n", + ret, master_map->id); + } 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; + + if (ret < 0) { + dev_warn_ratelimited(&chain->dev->udev->dev, + "UVC non compliance: Error %d populating cache of control %x\n", + ret, mapping->id); + } } =20 if (ctrl->info.flags & UVC_CTRL_FLAG_GET_DEF) { --- base-commit: 40ed9e9b2808beeb835bd0ed971fb364c285d39c change-id: 20241213-uvc-eaccess-755cc061a360 Best regards, --=20 Ricardo Ribalda