From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B65C23596F8; Mon, 19 Oct 2026 11:17:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=213.167.242.64 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792408641; cv=none; b=iPzUmoC4ZWiVKWPxmxmVYfz6YIL6TrT65LaN5mZmz5G2dQviTQ6m6HOGyV4xPplSR6WW0QLjL/RLBEygvHuTxUsJyBYY2CzYcAcjDmnlvU5PWrWRCI610J4Lh7bqZ4azriStjmQpwQ4teeEki/PlqzGKhNKZALlhpqbyrq+HAF8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792408641; c=relaxed/simple; bh=gu5Tu/8XaNtg1a6wZX38758V5qpZ+or3uZGrsS/pjmU=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=tLXKkzDu73rTQWpxn1LcczftdnNZMBHU5R4ZGq4Opo0TajnVwLvbefceHE27Qp1MgEoMtrG8xRfY4se1BN6ZiltefUAR2r2sxL4f1BH2n1sYNylc6cUDKQXjGL2k08v29PnU1xIDYKiZeU2RjcIZKrntOfM1BWKQRB0y3GE4bgU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=ideasonboard.com; spf=pass smtp.mailfrom=ideasonboard.com; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b=EzFBH6Hy; arc=none smtp.client-ip=213.167.242.64 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="EzFBH6Hy" Received: from killaraus.ideasonboard.com (2001-14ba-70f3-e800--a06.rev.dnainternet.fi [IPv6:2001:14ba:70f3:e800::a06]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id DD18615BF; Mon, 19 Oct 2026 13:15:07 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1792408508; bh=gu5Tu/8XaNtg1a6wZX38758V5qpZ+or3uZGrsS/pjmU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=EzFBH6HyraRGu5/qFZEj4vR/ODq58JryJIFneXG96JgBsmYwnCTXogpoby955pawa 450kSrqPhCJ7CBGz+W4/XQktkyiPwUkdmdE4g2sSBS7zQRgWOY3tlwt2NhJ/l10Lcv 2C9GJYPxOLP2+76sjV6d4p/T03T3tLGytJ5bNIEs= Date: Mon, 19 Oct 2026 14:17:12 +0300 From: Laurent Pinchart To: ostashow@gmail.com Cc: Hans de Goede , Mauro Carvalho Chehab , linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH] media: uvcvideo: Add quirk to retry SET_INTERFACE for SVBONY SV105C Message-ID: <20261019111712.GP595565@killaraus.ideasonboard.com> References: <20261019-sv105c-retry-set-interface-v1-1-ab2f08bc3fcb@gmail.com> Precedence: bulk X-Mailing-List: linux-media@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20261019-sv105c-retry-set-interface-v1-1-ab2f08bc3fcb@gmail.com> On Mon, Oct 19, 2026 at 02:07:28PM +0300, Ostashow Constantine via B4 Relay wrote: > From: Ostashow Constantine > > The SVBONY SV105C (0c45:636b, Sonix based) fails most SET_INTERFACE > requests that select a streaming alternate setting right after a > VS_COMMIT control. The request completes with -EPROTO, so > VIDIOC_STREAMON fails and capture applications see the camera > randomly failing to start. > > A usbmon capture of a failing VIDIOC_STREAMON: > > S Co:1:003:0 s 21 01 0200 0001 001a 26 = 01000104 15160500 ... > C Co:1:003:0 0 26 > > S Co:1:003:0 s 01 0b 0004 0001 0000 0 > C Co:1:003:0 -71 0 > S Co:1:003:0 s 01 0b 0000 0001 0000 0 > C Co:1:003:0 0 0 > > The failure rate is around 80% and does not depend on the alternate > setting (alt 1, the smallest one with 128 bytes per microframe, fails > as often as alt 6), on a delay between VS_COMMIT and SET_INTERFACE > (0 to 100 ms tested), or on USB autosuspend. SET_INTERFACE without a > preceding VS_COMMIT succeeded 15 out of 15 times, and an immediate > retry after the -EPROTO failure succeeded 15 out of 15 times. Once > streaming has started, the camera works reliably. It also works with > the Windows UVC driver. What does Windows do differently then ? > Add a UVC_QUIRK_RETRY_SET_INTERFACE quirk that retries SET_INTERFACE > up to three times when it fails with -EPROTO, and enable it for the > SV105C. With the quirk, 35 out of 35 stream starts succeeded, 29 of > them needed a retry, and no start needed more than one. > > lsusb -v: > > Bus 001 Device 003: ID 0c45:636b Microdia SVBONY SV105C > Negotiated speed: High Speed (480Mbps) > Device Descriptor: > bLength 18 > bDescriptorType 1 > bcdUSB 2.01 > bDeviceClass 239 Miscellaneous Device > bDeviceSubClass 2 [unknown] > bDeviceProtocol 1 Interface Association > bMaxPacketSize0 64 > idVendor 0x0c45 Microdia > idProduct 0x636b SVBONY SV105C > bcdDevice 1.00 > iManufacturer 2 Sonix Technology Co., Ltd. > iProduct 1 SVBONY SV105C > iSerial 3 SN0001 > bNumConfigurations 1 > Configuration Descriptor: > bLength 9 > bDescriptorType 2 > wTotalLength 0x032e > bNumInterfaces 2 > bConfigurationValue 1 > iConfiguration 0 > bmAttributes 0x80 > (Bus Powered) > MaxPower 500mA > Interface Association: > bLength 8 > bDescriptorType 11 > bFirstInterface 0 > bInterfaceCount 2 > bFunctionClass 14 Video > bFunctionSubClass 3 Video Interface Collection > bFunctionProtocol 0 > iFunction 5 > Interface Descriptor: > bLength 9 > bDescriptorType 4 > bInterfaceNumber 0 > bAlternateSetting 0 > bNumEndpoints 1 > bInterfaceClass 14 Video > bInterfaceSubClass 1 Video Control > bInterfaceProtocol 0 > iInterface 5 > VideoControl Interface Descriptor: > bLength 13 > bDescriptorType 36 > bDescriptorSubtype 1 (HEADER) > bcdUVC 1.00 > wTotalLength 0x0050 > dwClockFrequency 15.000000MHz > bInCollection 1 > baInterfaceNr( 0) 1 > VideoControl Interface Descriptor: > bLength 9 > bDescriptorType 36 > bDescriptorSubtype 3 (OUTPUT_TERMINAL) > bTerminalID 4 > wTerminalType 0x0101 USB Streaming > bAssocTerminal 0 > bSourceID 3 > iTerminal 0 > VideoControl Interface Descriptor: > bLength 29 > bDescriptorType 36 > bDescriptorSubtype 6 (EXTENSION_UNIT) > bUnitID 3 > guidExtensionCode {28f03370-6311-4a2e-ba2c-6890eb334016} > bNumControls 32 > bNrInPins 1 > baSourceID( 0) 2 > bControlSize 4 > bmControls( 0) 0x9f > bmControls( 1) 0x07 > bmControls( 2) 0x07 > bmControls( 3) 0x07 > iExtension 0 > VideoControl Interface Descriptor: > bLength 18 > bDescriptorType 36 > bDescriptorSubtype 2 (INPUT_TERMINAL) > bTerminalID 1 > wTerminalType 0x0201 Camera Sensor > bAssocTerminal 0 > iTerminal 0 > wObjectiveFocalLengthMin 0 > wObjectiveFocalLengthMax 0 > wOcularFocalLength 0 > bControlSize 3 > bmControls 0x0000000e > Auto-Exposure Mode > Auto-Exposure Priority > Exposure Time (Absolute) > VideoControl Interface Descriptor: > bLength 11 > bDescriptorType 36 > bDescriptorSubtype 5 (PROCESSING_UNIT) > Warning: Descriptor too short > bUnitID 2 > bSourceID 1 > wMaxMultiplier 0 > bControlSize 2 > bmControls 0x0000177f > Brightness > Contrast > Hue > Saturation > Sharpness > Gamma > White Balance Temperature > Backlight Compensation > Gain > Power Line Frequency > White Balance Temperature, Auto > iProcessing 0 > bmVideoStandards 0x31 > None > NTSC - 625/50 > PAL - 525/60 > Endpoint Descriptor: > bLength 7 > bDescriptorType 5 > bEndpointAddress 0x83 EP 3 IN > bmAttributes 3 > Transfer Type Interrupt > Synch Type None > Usage Type Data > wMaxPacketSize 0x0010 1x 16 bytes > bInterval 6 > VideoControl Endpoint Descriptor: > bLength 5 > bDescriptorType 37 > bDescriptorSubtype 3 (EP_INTERRUPT) > wMaxTransferSize 128 > Interface Descriptor: > bLength 9 > bDescriptorType 4 > bInterfaceNumber 1 > bAlternateSetting 0 > bNumEndpoints 0 > bInterfaceClass 14 Video > bInterfaceSubClass 2 Video Streaming > bInterfaceProtocol 0 > iInterface 0 > VideoStreaming Interface Descriptor: > bLength 15 > bDescriptorType 36 > bDescriptorSubtype 1 (INPUT_HEADER) > bNumFormats 2 > wTotalLength 0x024f > bEndpointAddress 0x81 EP 1 IN > bmInfo 0 > bTerminalLink 4 > bStillCaptureMethod 2 > bTriggerSupport 1 > bTriggerUsage 1 > bControlSize 1 > bmaControls( 0) 0 > bmaControls( 1) 0 > VideoStreaming Interface Descriptor: > bLength 11 > bDescriptorType 36 > bDescriptorSubtype 6 (FORMAT_MJPEG) > bFormatIndex 1 > bNumFrameDescriptors 8 > bFlags 0 > Fixed-size samples: No > bDefaultFrameIndex 1 > bAspectRatioX 0 > bAspectRatioY 0 > bmInterlaceFlags 0x00 > Interlaced stream or variable: No > Fields per frame: 1 fields > Field 1 first: No > Field pattern: Field 1 only > bCopyProtect 0 > VideoStreaming Interface Descriptor: > bLength 30 > bDescriptorType 36 > bDescriptorSubtype 7 (FRAME_MJPEG) > bFrameIndex 1 > bmCapabilities 0x00 > Still image unsupported > wWidth 1920 > wHeight 1080 > dwMinBitRate 995328000 > dwMaxBitRate 995328000 > dwMaxVideoFrameBufferSize 4147789 > dwDefaultFrameInterval 333333 > bFrameIntervalType 1 > dwFrameInterval( 0) 333333 > VideoStreaming Interface Descriptor: > bLength 30 > bDescriptorType 36 > bDescriptorSubtype 7 (FRAME_MJPEG) > bFrameIndex 2 > bmCapabilities 0x00 > Still image unsupported > wWidth 1280 > wHeight 1024 > dwMinBitRate 629145600 > dwMaxBitRate 629145600 > dwMaxVideoFrameBufferSize 2622029 > dwDefaultFrameInterval 333333 > bFrameIntervalType 1 > dwFrameInterval( 0) 333333 > VideoStreaming Interface Descriptor: > bLength 30 > bDescriptorType 36 > bDescriptorSubtype 7 (FRAME_MJPEG) > bFrameIndex 3 > bmCapabilities 0x00 > Still image unsupported > wWidth 1280 > wHeight 960 > dwMinBitRate 589824000 > dwMaxBitRate 589824000 > dwMaxVideoFrameBufferSize 2458189 > dwDefaultFrameInterval 333333 > bFrameIntervalType 1 > dwFrameInterval( 0) 333333 > VideoStreaming Interface Descriptor: > bLength 30 > bDescriptorType 36 > bDescriptorSubtype 7 (FRAME_MJPEG) > bFrameIndex 4 > bmCapabilities 0x00 > Still image unsupported > wWidth 1280 > wHeight 720 > dwMinBitRate 442368000 > dwMaxBitRate 442368000 > dwMaxVideoFrameBufferSize 1843789 > dwDefaultFrameInterval 333333 > bFrameIntervalType 1 > dwFrameInterval( 0) 333333 > VideoStreaming Interface Descriptor: > bLength 30 > bDescriptorType 36 > bDescriptorSubtype 7 (FRAME_MJPEG) > bFrameIndex 5 > bmCapabilities 0x00 > Still image unsupported > wWidth 800 > wHeight 600 > dwMinBitRate 230400000 > dwMaxBitRate 230400000 > dwMaxVideoFrameBufferSize 960589 > dwDefaultFrameInterval 333333 > bFrameIntervalType 1 > dwFrameInterval( 0) 333333 > VideoStreaming Interface Descriptor: > bLength 30 > bDescriptorType 36 > bDescriptorSubtype 7 (FRAME_MJPEG) > bFrameIndex 6 > bmCapabilities 0x00 > Still image unsupported > wWidth 640 > wHeight 480 > dwMinBitRate 147456000 > dwMaxBitRate 147456000 > dwMaxVideoFrameBufferSize 614989 > dwDefaultFrameInterval 333333 > bFrameIntervalType 1 > dwFrameInterval( 0) 333333 > VideoStreaming Interface Descriptor: > bLength 30 > bDescriptorType 36 > bDescriptorSubtype 7 (FRAME_MJPEG) > bFrameIndex 7 > bmCapabilities 0x00 > Still image unsupported > wWidth 480 > wHeight 640 > dwMinBitRate 147456000 > dwMaxBitRate 147456000 > dwMaxVideoFrameBufferSize 614989 > dwDefaultFrameInterval 333333 > bFrameIntervalType 1 > dwFrameInterval( 0) 333333 > VideoStreaming Interface Descriptor: > bLength 30 > bDescriptorType 36 > bDescriptorSubtype 7 (FRAME_MJPEG) > bFrameIndex 8 > bmCapabilities 0x00 > Still image unsupported > wWidth 1920 > wHeight 1080 > dwMinBitRate 995328000 > dwMaxBitRate 995328000 > dwMaxVideoFrameBufferSize 4147789 > dwDefaultFrameInterval 333333 > bFrameIntervalType 1 > dwFrameInterval( 0) 333333 > VideoStreaming Interface Descriptor: > bLength 34 > bDescriptorType 36 > bDescriptorSubtype 3 (STILL_IMAGE_FRAME) > bEndpointAddress 0x00 EP 0 OUT > bNumImageSizePatterns 7 > wWidth( 0) 1920 > wHeight( 0) 1080 > wWidth( 1) 1280 > wHeight( 1) 720 > wWidth( 2) 800 > wHeight( 2) 600 > wWidth( 3) 640 > wHeight( 3) 480 > wWidth( 4) 640 > wHeight( 4) 360 > wWidth( 5) 320 > wHeight( 5) 240 > wWidth( 6) 320 > wHeight( 6) 180 > bNumCompressionPatterns 0 > VideoStreaming Interface Descriptor: > bLength 27 > bDescriptorType 36 > bDescriptorSubtype 4 (FORMAT_UNCOMPRESSED) > bFormatIndex 2 > bNumFrameDescriptors 8 > guidFormat {32595559-0000-0010-8000-00aa00389b71} > bBitsPerPixel 16 > bDefaultFrameIndex 1 > bAspectRatioX 0 > bAspectRatioY 0 > bmInterlaceFlags 0x00 > Interlaced stream or variable: No > Fields per frame: 2 fields > Field 1 first: No > Field pattern: Field 1 only > bCopyProtect 0 > VideoStreaming Interface Descriptor: > bLength 30 > bDescriptorType 36 > bDescriptorSubtype 5 (FRAME_UNCOMPRESSED) > bFrameIndex 1 > bmCapabilities 0x00 > Still image unsupported > wWidth 1920 > wHeight 1080 > dwMinBitRate 165888000 > dwMaxBitRate 165888000 > dwMaxVideoFrameBufferSize 4147200 > dwDefaultFrameInterval 2000000 > bFrameIntervalType 1 > dwFrameInterval( 0) 2000000 > VideoStreaming Interface Descriptor: > bLength 30 > bDescriptorType 36 > bDescriptorSubtype 5 (FRAME_UNCOMPRESSED) > bFrameIndex 2 > bmCapabilities 0x00 > Still image unsupported > wWidth 1280 > wHeight 1024 > dwMinBitRate 104857600 > dwMaxBitRate 104857600 > dwMaxVideoFrameBufferSize 2621440 > dwDefaultFrameInterval 2000000 > bFrameIntervalType 1 > dwFrameInterval( 0) 2000000 > VideoStreaming Interface Descriptor: > bLength 30 > bDescriptorType 36 > bDescriptorSubtype 5 (FRAME_UNCOMPRESSED) > bFrameIndex 3 > bmCapabilities 0x00 > Still image unsupported > wWidth 1280 > wHeight 960 > dwMinBitRate 98304000 > dwMaxBitRate 98304000 > dwMaxVideoFrameBufferSize 2457600 > dwDefaultFrameInterval 2000000 > bFrameIntervalType 1 > dwFrameInterval( 0) 2000000 > VideoStreaming Interface Descriptor: > bLength 30 > bDescriptorType 36 > bDescriptorSubtype 5 (FRAME_UNCOMPRESSED) > bFrameIndex 4 > bmCapabilities 0x00 > Still image unsupported > wWidth 1280 > wHeight 720 > dwMinBitRate 147456000 > dwMaxBitRate 147456000 > dwMaxVideoFrameBufferSize 1843200 > dwDefaultFrameInterval 1000000 > bFrameIntervalType 1 > dwFrameInterval( 0) 1000000 > VideoStreaming Interface Descriptor: > bLength 30 > bDescriptorType 36 > bDescriptorSubtype 5 (FRAME_UNCOMPRESSED) > bFrameIndex 5 > bmCapabilities 0x00 > Still image unsupported > wWidth 800 > wHeight 600 > dwMinBitRate 153600000 > dwMaxBitRate 153600000 > dwMaxVideoFrameBufferSize 960000 > dwDefaultFrameInterval 500000 > bFrameIntervalType 1 > dwFrameInterval( 0) 500000 > VideoStreaming Interface Descriptor: > bLength 30 > bDescriptorType 36 > bDescriptorSubtype 5 (FRAME_UNCOMPRESSED) > bFrameIndex 6 > bmCapabilities 0x00 > Still image unsupported > wWidth 640 > wHeight 480 > dwMinBitRate 147456000 > dwMaxBitRate 147456000 > dwMaxVideoFrameBufferSize 614400 > dwDefaultFrameInterval 333333 > bFrameIntervalType 1 > dwFrameInterval( 0) 333333 > VideoStreaming Interface Descriptor: > bLength 30 > bDescriptorType 36 > bDescriptorSubtype 5 (FRAME_UNCOMPRESSED) > bFrameIndex 7 > bmCapabilities 0x00 > Still image unsupported > wWidth 480 > wHeight 640 > dwMinBitRate 147456000 > dwMaxBitRate 147456000 > dwMaxVideoFrameBufferSize 614400 > dwDefaultFrameInterval 333333 > bFrameIntervalType 1 > dwFrameInterval( 0) 333333 > VideoStreaming Interface Descriptor: > bLength 30 > bDescriptorType 36 > bDescriptorSubtype 5 (FRAME_UNCOMPRESSED) > bFrameIndex 8 > bmCapabilities 0x00 > Still image unsupported > wWidth 1920 > wHeight 1080 > dwMinBitRate 165888000 > dwMaxBitRate 165888000 > dwMaxVideoFrameBufferSize 4147200 > dwDefaultFrameInterval 2000000 > bFrameIntervalType 1 > dwFrameInterval( 0) 2000000 > VideoStreaming Interface Descriptor: > bLength 18 > bDescriptorType 36 > bDescriptorSubtype 3 (STILL_IMAGE_FRAME) > bEndpointAddress 0x00 EP 0 OUT > bNumImageSizePatterns 3 > wWidth( 0) 1920 > wHeight( 0) 1080 > wWidth( 1) 1280 > wHeight( 1) 720 > wWidth( 2) 640 > wHeight( 2) 480 > bNumCompressionPatterns 0 > VideoStreaming Interface Descriptor: > bLength 6 > bDescriptorType 36 > bDescriptorSubtype 13 (COLORFORMAT) > bColorPrimaries 1 (BT.709,sRGB) > bTransferCharacteristics 1 (BT.709) > bMatrixCoefficients 4 (SMPTE 170M (BT.601)) > Interface Descriptor: > bLength 9 > bDescriptorType 4 > bInterfaceNumber 1 > bAlternateSetting 1 > bNumEndpoints 1 > bInterfaceClass 14 Video > bInterfaceSubClass 2 Video Streaming > bInterfaceProtocol 0 > iInterface 0 > Endpoint Descriptor: > bLength 7 > bDescriptorType 5 > bEndpointAddress 0x81 EP 1 IN > bmAttributes 5 > Transfer Type Isochronous > Synch Type Asynchronous > Usage Type Data > wMaxPacketSize 0x0080 1x 128 bytes > bInterval 1 > Interface Descriptor: > bLength 9 > bDescriptorType 4 > bInterfaceNumber 1 > bAlternateSetting 2 > bNumEndpoints 1 > bInterfaceClass 14 Video > bInterfaceSubClass 2 Video Streaming > bInterfaceProtocol 0 > iInterface 0 > Endpoint Descriptor: > bLength 7 > bDescriptorType 5 > bEndpointAddress 0x81 EP 1 IN > bmAttributes 5 > Transfer Type Isochronous > Synch Type Asynchronous > Usage Type Data > wMaxPacketSize 0x0100 1x 256 bytes > bInterval 1 > Interface Descriptor: > bLength 9 > bDescriptorType 4 > bInterfaceNumber 1 > bAlternateSetting 3 > bNumEndpoints 1 > bInterfaceClass 14 Video > bInterfaceSubClass 2 Video Streaming > bInterfaceProtocol 0 > iInterface 0 > Endpoint Descriptor: > bLength 7 > bDescriptorType 5 > bEndpointAddress 0x81 EP 1 IN > bmAttributes 5 > Transfer Type Isochronous > Synch Type Asynchronous > Usage Type Data > wMaxPacketSize 0x0320 1x 800 bytes > bInterval 1 > Interface Descriptor: > bLength 9 > bDescriptorType 4 > bInterfaceNumber 1 > bAlternateSetting 4 > bNumEndpoints 1 > bInterfaceClass 14 Video > bInterfaceSubClass 2 Video Streaming > bInterfaceProtocol 0 > iInterface 0 > Endpoint Descriptor: > bLength 7 > bDescriptorType 5 > bEndpointAddress 0x81 EP 1 IN > bmAttributes 5 > Transfer Type Isochronous > Synch Type Asynchronous > Usage Type Data > wMaxPacketSize 0x0b20 2x 800 bytes > bInterval 1 > Interface Descriptor: > bLength 9 > bDescriptorType 4 > bInterfaceNumber 1 > bAlternateSetting 5 > bNumEndpoints 1 > bInterfaceClass 14 Video > bInterfaceSubClass 2 Video Streaming > bInterfaceProtocol 0 > iInterface 0 > Endpoint Descriptor: > bLength 7 > bDescriptorType 5 > bEndpointAddress 0x81 EP 1 IN > bmAttributes 5 > Transfer Type Isochronous > Synch Type Asynchronous > Usage Type Data > wMaxPacketSize 0x1320 3x 800 bytes > bInterval 1 > Interface Descriptor: > bLength 9 > bDescriptorType 4 > bInterfaceNumber 1 > bAlternateSetting 6 > bNumEndpoints 1 > bInterfaceClass 14 Video > bInterfaceSubClass 2 Video Streaming > bInterfaceProtocol 0 > iInterface 0 > Endpoint Descriptor: > bLength 7 > bDescriptorType 5 > bEndpointAddress 0x81 EP 1 IN > bmAttributes 5 > Transfer Type Isochronous > Synch Type Asynchronous > Usage Type Data > wMaxPacketSize 0x1400 3x 1024 bytes > bInterval 1 > > Cc: stable@vger.kernel.org > Assisted-by: claude-opus-5-5 > Signed-off-by: Ostashow Constantine > --- > Notes for reviewers (not part of the commit message): > > Testing: > - Runtime-tested on a Raspberry Pi 4 (VL805 xHCI) running 6.18.57, with > this patch applied to the 6.18.57 uvcvideo sources (it applies with > line offsets only). Results are in the commit message. Before the > patch, 3/20 and 5/20 stream starts succeeded. > - Built with W=1 without new warnings: as part of the 6.18.57 module, > and the patched media/next sources against 6.18 headers plus the > media/next include/linux/usb/uvc.h. > - Not runtime-tested on media/next itself, and not tested on other host > controllers (e.g. x86 xHCI). I can't tell whether the failure depends > on the host controller. > > Tool disclosure (Documentation/process/generated-content.rst): > The root-cause analysis (usbmon capture, libusb experiments varying the > alternate setting, the delay after VS_COMMIT and retries), the patch and > this changelog were produced by an AI coding assistant (Claude Code, > claude-opus-5-5) in an interactive session, at my request, on my > hardware. I have reviewed the patch and take responsibility for it. > --- > drivers/media/usb/uvc/uvc_driver.c | 9 +++++++++ > drivers/media/usb/uvc/uvc_video.c | 14 ++++++++++++++ > drivers/media/usb/uvc/uvcvideo.h | 1 + > 3 files changed, 24 insertions(+) > > diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c > index cbc145697..9e1f855cd 100644 > --- a/drivers/media/usb/uvc/uvc_driver.c > +++ b/drivers/media/usb/uvc/uvc_driver.c > @@ -2928,6 +2928,15 @@ static const struct usb_device_id uvc_ids[] = { > .bInterfaceSubClass = 1, > .bInterfaceProtocol = 0, > .driver_info = UVC_INFO_QUIRK(UVC_QUIRK_MJPEG_NO_EOF) }, > + /* SVBONY SV105C */ > + { .match_flags = USB_DEVICE_ID_MATCH_DEVICE > + | USB_DEVICE_ID_MATCH_INT_INFO, > + .idVendor = 0x0c45, > + .idProduct = 0x636b, > + .bInterfaceClass = USB_CLASS_VIDEO, > + .bInterfaceSubClass = 1, > + .bInterfaceProtocol = 0, > + .driver_info = UVC_INFO_QUIRK(UVC_QUIRK_RETRY_SET_INTERFACE) }, > /* MT6227 */ > { .match_flags = USB_DEVICE_ID_MATCH_DEVICE > | USB_DEVICE_ID_MATCH_INT_INFO, > diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c > index a92a986ab..3a3b1d1d7 100644 > --- a/drivers/media/usb/uvc/uvc_video.c > +++ b/drivers/media/usb/uvc/uvc_video.c > @@ -2100,6 +2100,20 @@ static int uvc_video_start_transfer(struct uvc_streaming *stream, > } > > ret = usb_set_interface(stream->dev->udev, intfnum, altsetting); > + > + /* > + * Some devices, namely the SVBONY SV105C, fail most of the > + * SET_INTERFACE requests that follow a VS_COMMIT control with > + * a protocol error. Retrying the request immediately succeeds. > + */ > + for (i = 0; ret == -EPROTO && i < 3 && > + (stream->dev->quirks & UVC_QUIRK_RETRY_SET_INTERFACE); ++i) { > + uvc_dbg(stream->dev, VIDEO, > + "SET_INTERFACE failed (%d), retrying\n", ret); > + ret = usb_set_interface(stream->dev->udev, intfnum, > + altsetting); > + } > + > if (ret < 0) > return ret; > > diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h > index af8cef94f..19851c3d2 100644 > --- a/drivers/media/usb/uvc/uvcvideo.h > +++ b/drivers/media/usb/uvc/uvcvideo.h > @@ -81,6 +81,7 @@ > #define UVC_QUIRK_INVALID_DEVICE_SOF 0x00010000 > #define UVC_QUIRK_MJPEG_NO_EOF 0x00020000 > #define UVC_QUIRK_MSXU_META 0x00040000 > +#define UVC_QUIRK_RETRY_SET_INTERFACE 0x00080000 > > /* Format flags */ > #define UVC_FMT_FLAG_COMPRESSED 0x00000001 > > --- > base-commit: d7e7bca7169873b46e857c025c10f3336c1258d8 > change-id: 20261019-sv105c-retry-set-interface-759a92a1e7b5 -- Regards, Laurent Pinchart