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Hello, I need to change bInterval from 1ms to 4ms, I believe it will lower pressure on the system. If USB interrupts will occur not every 1ms, but 4ms.
https://learn.microsoft.com/en-us/windows-hardware/drivers/ddi/usbspec/ns-usbspec-_usb_endpoint_descriptor - I read here I need to change bInterval from 4 to 32. And Transfer type from isochronous to interrupt. I think I changed that and tested with this https://www.thesycon.de/eng/usb_descriptordumper.shtml
I tried these settings:
bmAttributes 0b0011
wMaxPacketSize 482ch2bytes*4ms= 768 bytes
bInterval 0x6 = 2^(6-1) microframes = 32 * 125us = 4000us
/* ------------------------- Endpoint Descriptor */
/* [242] 0 bLength, bDescriptorType */ 7, 0x05,
/* [244] 2 bEndpointAddress */ 0x83,
/* [245] 3 bmAttributes : 0x0D (Sync|ISO) */ 0x03,
/* [246] 4 wMaxPacketSize : 0xC0 (48kHz * 2 channels * 2 bytes width) */ 0x00, 0x03,
/* [248] 6 bInterval : 0x04 (1ms) */ 0x6,
The whole descriptor is below:
/* -------------------------- Device Descriptor */
/* [0 ] 0 bLength, bDescriptorType */ 0x12, 0x01,
/* [2 ] 2 bcdUSB : 0x200 (2.00) */ 0x00, 0x02,
/* [4 ] 4 bDeviceClass : 0x00 (see interface) */ 0xEF,
/* [5 ] 5 bDeviceSubClass : 0x00 (see interface) */ 0x02,
/* [6 ] 6 bDeviceProtocol : 0x00 (see interface) */ 0x01,
/* [7 ] 7 bMaxPacketSize0 */ 64,
/* [8 ] 8 idVendor, idProduct */ 0x84, 0x84, 0x03, 0x00,
/* [12] 12 bcdDevice */ 0x00, 0x02,
/* [14] 14 iManufacturer, iProduct, iSerialNumber */ 1, 2, 3,
/* [17] 17 bNumConfigurations */ 1,
/* ---------------- Device Qualifier Descriptor */
/* [18] 0 bLength, bDescriptorType */ 0x0A, 0x06,
/* [20] 2 bcdUSB : 0x200 (2.00) */ 0x00,0x02,
/* [22] 4 bDeviceClass : 0x00 (see interface) */ 0xEF,
/* [23] 5 bDeviceSubClass : 0x00 (see interface) */ 0x02,
/* [24] 6 bDeviceProtocol : 0x00 (see interface) */ 0x01,
/* [25] 7 bMaxPacketSize0 */ 64,
/* [26] 8 bNumConfigurations */ 1,
/* [27] 9 bReserved */ 0,
/* --- Configuration Descriptor (9+8+73+55=145, 0x91) */
/* [28] 0 bLength, bDescriptorType */ 9, 0x02,
/* [30] 2 wTotalLength */ 229, 0x00,
/* [32] 4 bNumInterfaces, bConfigurationValue */ 3, 1,
/* [34] 6 iConfiguration */ 0,
/* [35] 7 bmAttributes, bMaxPower */ 192, 50,
/* ----------- Interface Association Descriptor */
/* [37] 0 bLength, bDescriptorType */ 8, 0x0B,
/* [39] 2 bFirstInterface, bInterfaceCount */ 0, 3,
/* [41] 4 bFunctionClass : 0x01 (Audio) */ 0x01,
/* [42] 5 bFunctionSubClass : 0x00 (UNDEFINED) */ 0x00,
/* [43] 6 bFunctionProtocol : 0x20 (VERSION_02_00) */ 0x20,
/* [44] 7 iFunction */ 0,
/* --- Interface Descriptor #0: Control (9+64=73) */
/* [45] 0 bLength, bDescriptorType */ 9, 0x04,
/* [47] 2 bInterfaceNumber, bAlternateSetting */ 0, 0,
/* [49] 4 bNumEndpoints */ 0,
/* [50] 5 bInterfaceClass : 0x01 (Audio) */ 0x01,
/* [51] 6 bInterfaceSubClass : 0x01 (AudioControl) */ 0x01,
/* [52] 7 bInterfaceProtocol : 0x20 (VERSION_02_00) */ 0x20,
/* [53] 8 iInterface */ 0,
/* --- Audio 2.0 AC Interface Header Descriptor (9+8+17+18+12=64, 0x40) */
/* [54] 0 bLength */ 9,
/* [55] 1 bDescriptorType, bDescriptorSubtype */ 0x24, 0x01,
/* [57] 3 bcdADC */ 0x00, 0x02,
/* [59] 5 bCategory : 0x04 (Headset) */ 0x08,
/* [60] 6 wTotalLength */ 93, 0,
/* [62] 8 bmControls */ 0x00,
/* -------- Audio 2.0 AC Clock Source Descriptor */
/* [63] 0 bLength */ 8,
/* [64] 1 bDescriptorType, bDescriptorSubtype */ 0x24, 0x0A,
/* [66] 3 bClockID */ 24,
/* [67] 4 bmAttributes : 0x05 (Sync|InternalFixedClk) */ 0x01,
/* [68] 5 bmControls : 0x01 (FreqReadOnly) */ 0x01,
/* [69] 6 bAssocTerminal, iClockSource */ 0x00, 0,
/* ------ Audio 2.0 AC Input Terminal Descriptor */
/* [71] 0 bLength */ 17,
/* [72] 1 bDescriptorType, bDescriptorSubtype */ 0x24, 0x02,
/* [74] 3 bTerminalID */ 0x12,
/* [75] 4 wTerminalType : 0x0101 (USB Streaming) */ 0x01, 0x01,
/* [77] 6 bAssocTerminal, bCSourceID */ 0x00, 0x18,
/* [79] 8 bNrChannels */ 2,
/* [80] 9 bmChannelConfig */ 0x03, 0x00, 0x00, 0x00,
/* [84] 13 iChannelNames, bmControls, iTerminal */ 0, 0x00, 0x00, 0,
/* -------- Audio 2.0 AC Feature Unit Descriptor */
/* [88] 0 bLength */ 18,
/* [89] 1 bDescriptorType, bDescriptorSubtype */ 0x24, 0x06,
/* [91] 3 bUnitID, bSourceID */ 0x16, 0x12,
/* [93] 5 bmaControls(0) : 0x0F (VolumeRW|MuteRW) */ 0x0F, 0x00, 0x00, 0x00,
/* [97] 9 bmaControls(1) : 0x00000000 */ 0x00, 0x00, 0x00, 0x00,
/* [101] 13 bmaControls(1) : 0x00000000 */ 0x00, 0x00, 0x00, 0x00,
/* [105]. iFeature */ 0,
/* ----- Audio 2.0 AC Output Terminal Descriptor */
/* [106] 0 bLength */ 12,
/* [107] 1 bDescriptorType, bDescriptorSubtype */ 0x24, 0x03,
/* [109] 3 bTerminalID */ 0x14,
/* [110] 4 wTerminalType : 0x0301 (Speaker) */ 0x01, 0x03,
/* [112] 6 bAssocTerminal, bSourceID, bCSourceID */ 0x00, 0x16, 0x18,
/* [115] 9 bmControls, iTerminal */ 0x00, 0x00, 0,
/* ------ Audio 2.0 AC 2nd Input Terminal Descriptor */
/* [118] 0 bLength */ 17,
/* [119] 1 bDescriptorType, bDescriptorSubtype */ 0x24, 0x02,
/* [121] 3 bTerminalID */ 0x20,
/* [122] 4 wTerminalType : 0x0102 (Microphone) */ 0x01, 0x02,
/* [124] 6 bAssocTerminal, bCSourceID */ 0x00, 0x18,
/* [126] 8 bNrChannels */ 2,
/* [127] 9 bmChannelConfig */ 0x03, 0x00, 0x00, 0x00,
/* [131] 13 iChannelNames, bmControls, iTerminal */ 0, 0x00, 0x00, 0,
/* ----- Audio 2.0 AC 2nd Output Terminal Descriptor */
/* [135] 0 bLength */ 12,
/* [136] 1 bDescriptorType, bDescriptorSubtype */ 0x24, 0x03,
/* [138] 3 bTerminalID */ 0x22,
/* [139] 4 wTerminalType : 0x0101 (USB Streaming) */ 0x01, 0x01,
/* [141] 6 bAssocTerminal, bSourceID, bCSourceID */ 0x00, 0x20, 0x18,
/* [144] 9 bmControls, iTerminal */ 0x00, 0x00, 0,
/* --- Interface Descriptor #1: Stream OUT (9+9+16+6+7+8=55) */
/* [147] 0 bLength, bDescriptorType */ 9, 0x04,
/* [149] 2 bInterfaceNumber, bAlternateSetting */ 1, 0,
/* [151] 4 bNumEndpoints */ 0,
/* [152] 5 bInterfaceClass : 0x01 (Audio) */ 0x01,
/* [153] 6 bInterfaceSubClass : 0x01 (AudioStream) */ 0x02,
/* [154] 7 bInterfaceProtocol : 0x20 (VERSION_02_00) */ 0x20,
/* [155] 8 iInterface */ 0,
/* ----------------------- Interface Descriptor */
/* [156] 0 bLength, bDescriptorType */ 9, 0x04,
/* [158] 2 bInterfaceNumber, bAlternateSetting */ 1, 1,
/* [160] 4 bNumEndpoints */ 1,
/* [161] 5 bInterfaceClass : 0x01 (Audio) */ 0x01,
/* [162] 6 bInterfaceSubClass : 0x01 (AudioStream) */ 0x02,
/* [163] 7 bInterfaceProtocol : 0x20 (VERSION_02_00) */ 0x20,
/* [164] 8 iInterface */ 0,
/* ----------- Audio 2.0 AS Interface Descriptor */
/* [165] 0 bLength */ 16,
/* [166] 1 bDescriptorType, bDescriptorSubtype */ 0x24, 0x01,
/* [168] 3 bTerminalLink, bmControls */ 0x12, 0x00,
/* [170] 5 bFormatType : 0x01 (FORMAT_TYPE_I) */ 0x01,
/* [171] 6 bmFormats : 0x000000001 (PCM) */ 0x01, 0x00, 0x00, 0x00,
/* [175] 10 bNrChannels */ 2,
/* [176] 11 bmChannelConfig */ 0x03, 0x00, 0x00, 0x00,
/* [180] 15 iChannelNames */ 0,
/* --------- Audio 2.0 AS Format Type Descriptor */
/* [181] 0 bLength */ 6,
/* [182] 1 bDescriptorType, bDescriptorSubtype */ 0x24, 0x02,
/* [184] 3 bFormatType : 0x01 (FORMAT_TYPE_I) */ 0x01,
/* [185] 4 bSubslotSize, bBitResolution */ 2, 16,
/* ------------------------- Endpoint Descriptor */
/* [187] 0 bLength, bDescriptorType */ 7, 0x05,
/* [189] 2 bEndpointAddress */ 0x01,
/* [190] 3 bmAttributes : 0x0D (Sync|ISO) */ 0x0D,
/* [191] 4 wMaxPacketSize : 0x0100 (256) */ 0xC0, 0x00,
/* [193] 6 bInterval : 0x04 (1ms) */ 4,
/* - Audio 2.0 AS ISO Audio Data Endpoint Descriptor */
/* [194] 0 bLength */ 8,
/* [195] 1 bDescriptorType, bDescriptorSubtype */ 0x25, 0x01,
/* [197] 3 bmAttributes, bmControls */ 0x00, 0x00,
/* [199] 5 bLockDelayUnits, wLockDelay */ 0x00, 0x00, 0x00,
/* --- Interface Descriptor #1: Stream IN Mic (9+9+16+6+7+8=55) */
/* [202] 0 bLength, bDescriptorType */ 9, 0x04,
/* [204] 2 bInterfaceNumber, bAlternateSetting */ 2, 0,
/* [206] 4 bNumEndpoints */ 0,
/* [207] 5 bInterfaceClass : 0x01 (Audio) */ 0x01,
/* [208] 6 bInterfaceSubClass : 0x01 (AudioStream) */ 0x02,
/* [209] 7 bInterfaceProtocol : 0x20 (VERSION_02_00) */ 0x20,
/* [210] 8 iInterface */ 0,
/* ----------------------- Interface Descriptor */
/* [211] 0 bLength, bDescriptorType */ 9, 0x04,
/* [213] 2 bInterfaceNumber, bAlternateSetting */ 2, 1,
/* [215] 4 bNumEndpoints */ 1,
/* [216] 5 bInterfaceClass : 0x01 (Audio) */ 0x01,
/* [217] 6 bInterfaceSubClass : 0x01 (AudioStream) */ 0x02,
/* [218] 7 bInterfaceProtocol : 0x20 (VERSION_02_00) */ 0x20,
/* [219] 8 iInterface */ 0,
/* ----------- Audio 2.0 AS Interface Descriptor */
/* [220] 0 bLength */ 16,
/* [221] 1 bDescriptorType, bDescriptorSubtype */ 0x24, 0x01,
/* [223] 3 bTerminalLink, bmControls */ 0x22, 0x05,
/* [225] 5 bFormatType : 0x01 (FORMAT_TYPE_I) */ 0x01,
/* [226] 6 bmFormats : 0x000000001 (PCM) */ 0x01, 0x00, 0x00, 0x00,
/* [230] 10 bNrChannels */ 2,
/* [231] 11 bmChannelConfig */ 0x03, 0x00, 0x00, 0x00,
/* [235] 15 iChannelNames */ 0,
/* --------- Audio 2.0 AS Format Type Descriptor */
/* [236] 0 bLength */ 6,
/* [227] 1 bDescriptorType, bDescriptorSubtype */ 0x24, 0x02,
/* [239] 3 bFormatType : 0x01 (FORMAT_TYPE_I) */ 0x01,
/* [240] 4 bSubslotSize, bBitResolution */ 2, 16,
/* ------------------------- Endpoint Descriptor */
/* [242] 0 bLength, bDescriptorType */ 7, 0x05,
/* [244] 2 bEndpointAddress */ 0x83,
/* [245] 3 bmAttributes : 0x0D (Sync|ISO) */ 0x0D,
/* [246] 4 wMaxPacketSize : 0xC0 (48kHz * 2 channels * 2 bytes width) */ 0xC0, 0x00,
/* [248] 6 bInterval : 0x04 (1ms) */ 0x4,
/* - Audio 2.0 AS ISO Audio Data Endpoint Descriptor */
/* [249] 0 bLength */ 8,
/* [250] 1 bDescriptorType, bDescriptorSubtype */ 0x25, 0x01,
/* [252] 3 bmAttributes, bmControls */ 0x00, 0x00,
/* [254] 5 bLockDelayUnits, wLockDelay */ 0x00, 0x00, 0x00,
Hi @Serhii Cherkasov Greetings! Thank you for posting this question here. Our community SMEs on this this topic will review this question and get back to you with more details as soon as possible. Please stay tuned to this for updates in the next two days.
I returned to this issue, I read that i need to switch transfer type to interrupt. So I changed from bmAttributes to 00000011. And device appeared in the device manager but with error: This device cannot start. (Code 10)
Hi @Serhii Cherkasov Apologies for the delay in getting back to you on this. Thank you for sharing your latest observations and findings on this. We are reviewing them internally with the Product team. We will get back to you with more findings on this. I understand that this situation may have caused some inconvenience, and I want to express my gratitude for your efforts and patience in handling it.
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@Serhii Cherkasov The data endpoint for USB Audio must be isochronous endpoint, interrupt endpoint does not work.