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[34.88.36.11]) by smtp.gmail.com with ESMTPSA id 2adb3069b0e04-5b6166fbfacsm2548785e87.42.2026.09.07.14.16.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 07 Sep 2026 14:16:50 -0700 (PDT) From: Ricardo Ribalda Date: Mon, 07 Sep 2026 21:16:49 +0000 Subject: [PATCH] media: uvcvideo: Automatically handle cameras with invalid uvc_version 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: 7bit Message-Id: <20260907-uvc-version-v1-1-34e45dfe04de@chromium.org> X-B4-Tracking: v=1; b=H4sIAMApn2oC/6tWKk4tykwtVrJSqFYqSi3LLM7MzwNyDHUUlJIzE vPSU3UzU4B8JSMDIzMDSwNz3dKyZN2y1CKQOt3E1JTUtGQTYwuT5FQloI6CotS0zAqwadGxtbU A5SvzE10AAAA= X-Change-ID: 20260907-uvc-version-aedefc4384ce To: Laurent Pinchart , Hans de Goede , Mauro Carvalho Chehab Cc: Edwin Gatier , linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, Ricardo Ribalda X-Mailer: b4 0.14.3 Currently, the driver expects that cameras properly implement the spec version that they announce, and if they fail to do so, we do not continue probing the driver. To make drivers more fun, some vendors decided to announce that they are a UVC version that they are not. Until now, we handled those cameras via quirks. Unfortunately, reality has shown us that there are more cameras out there with an invalid uvc_version than we initially predicted. This patch tries to handle these cameras with an identity crisis automatically. We still shame them in dmesg. But now they will work. Signed-off-by: Ricardo Ribalda --- Hi Edwin, could you please try if this patch alone (without the previous one) works for you? Could you share the dmesg output with it? Thanks! --- drivers/media/usb/uvc/uvc_driver.c | 11 +++++++---- drivers/media/usb/uvc/uvc_video.c | 23 ++++++++++++++++++----- 2 files changed, 25 insertions(+), 9 deletions(-) diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c index e289cc71ba98..ca75f8d1ec46 100644 --- a/drivers/media/usb/uvc/uvc_driver.c +++ b/drivers/media/usb/uvc/uvc_driver.c @@ -1169,9 +1169,7 @@ static int uvc_parse_standard_control(struct uvc_device *dev, case UVC_VC_PROCESSING_UNIT: n = buflen >= 8 ? buffer[7] : 0; - p = dev->uvc_version >= 0x0110 ? 10 : 9; - - if (buflen < p + n) { + if (buflen < 9 + n) { uvc_dbg(dev, DESCR, "device %d videocontrol interface %d PROCESSING_UNIT error\n", udev->devnum, alts->desc.bInterfaceNumber); @@ -1188,7 +1186,12 @@ static int uvc_parse_standard_control(struct uvc_device *dev, unit->processing.bControlSize = buffer[7]; unit->processing.bmControls = (u8 *)unit + sizeof(*unit); memcpy(unit->processing.bmControls, &buffer[8], n); - if (dev->uvc_version >= 0x0110) + + /* + * We are not using bmVideoStandards, so there is no need to + * warn the user if it is missing. + */ + if (dev->uvc_version >= 0x0110 && buflen >= (n + 10)) unit->processing.bmVideoStandards = buffer[9+n]; uvc_entity_set_name(dev, unit, "Processing", buffer[8+n]); diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c index fc3536a4399f..58e1c1fa6af2 100644 --- a/drivers/media/usb/uvc/uvc_video.c +++ b/drivers/media/usb/uvc/uvc_video.c @@ -273,6 +273,8 @@ static void uvc_fixup_video_ctrl(struct uvc_streaming *stream, } } +#define UVC_VIDEO_CTRL_MIN_SIZE 26 + static size_t uvc_video_ctrl_size(struct uvc_streaming *stream) { /* @@ -280,7 +282,7 @@ static size_t uvc_video_ctrl_size(struct uvc_streaming *stream) * on the protocol version. */ if (stream->dev->uvc_version < 0x0110) - return 26; + return UVC_VIDEO_CTRL_MIN_SIZE; else if (stream->dev->uvc_version < 0x0150) return 34; else @@ -319,7 +321,8 @@ static int uvc_get_video_ctrl(struct uvc_streaming *stream, ctrl->wCompQuality = le16_to_cpup((__le16 *)data); ret = 0; goto out; - } else if (query == UVC_GET_DEF && probe == 1 && ret != size) { + } else if (query == UVC_GET_DEF && probe == 1 && + ret < UVC_VIDEO_CTRL_MIN_SIZE) { /* * Many cameras don't support the GET_DEF request on their * video probe control. Warn once and return, the caller will @@ -330,7 +333,7 @@ static int uvc_get_video_ctrl(struct uvc_streaming *stream, "Enabling workaround.\n"); ret = -EIO; goto out; - } else if (ret != size) { + } else if (ret < UVC_VIDEO_CTRL_MIN_SIZE) { dev_err(&stream->intf->dev, "Failed to query (%s) UVC %s control : %d (exp. %u).\n", uvc_query_name(query), probe ? "probe" : "commit", @@ -339,6 +342,12 @@ static int uvc_get_video_ctrl(struct uvc_streaming *stream, goto out; } + if (ret != size) + dev_warn_once(&stream->intf->dev, + "UVC non compliance: Query (%s) UVC %s control had a size of %d instead of %u.\n", + uvc_query_name(query), + probe ? "probe" : "commit", ret, size); + ctrl->bmHint = le16_to_cpup((__le16 *)&data[0]); ctrl->bFormatIndex = data[2]; ctrl->bFrameIndex = data[3]; @@ -351,7 +360,7 @@ static int uvc_get_video_ctrl(struct uvc_streaming *stream, ctrl->dwMaxVideoFrameSize = get_unaligned_le32(&data[18]); ctrl->dwMaxPayloadTransferSize = get_unaligned_le32(&data[22]); - if (size >= 34) { + if (ret >= 34) { ctrl->dwClockFrequency = get_unaligned_le32(&data[26]); ctrl->bmFramingInfo = data[30]; ctrl->bPreferedVersion = data[31]; @@ -412,11 +421,15 @@ static int uvc_set_video_ctrl(struct uvc_streaming *stream, ret = __uvc_query_ctrl(stream->dev, UVC_SET_CUR, 0, stream->intfnum, probe ? UVC_VS_PROBE_CONTROL : UVC_VS_COMMIT_CONTROL, data, size, uvc_timeout_param); - if (ret != size) { + if (ret < UVC_VIDEO_CTRL_MIN_SIZE) { dev_err(&stream->intf->dev, "Failed to set UVC %s control : %d (exp. %u).\n", probe ? "probe" : "commit", ret, size); ret = -EIO; + } else if (ret != size) { + dev_warn_once(&stream->intf->dev, + "UVC non compliance: Set UVC %s control had a size of %d instead of %u.\n", + probe ? "probe" : "commit", ret, size); } kfree(data); --- base-commit: f9536a8065d9eed0d9114878c56ffc4e5a18bdfc change-id: 20260907-uvc-version-aedefc4384ce Best regards, -- Ricardo Ribalda