On Wed, Jan 15, 2014 at 01:49:17PM -0200, Mauro Carvalho Chehab wrote: > Hi Martin, > > Em Wed, 11 Dec 2013 21:34:55 +0100 > Martin Kittel <li...@martin-kittel.de> escreveu: > > > Hi Mauro, hi Sean, > > > > thanks for considering the patch. I have added an updated version at the > > end of this mail. > > > > Regarding the info Sean was requesting, it is indeed an xhci hub. I also > > added the details of the remote itself. > > > > Please let me know if there is anything missing. > > > > Best wishes, > > > > Martin. > > > > > > lsusb -vvv > > ------ > > Bus 001 Device 002: ID 2304:0225 Pinnacle Systems, Inc. Remote Kit > > Infrared Transceiver > > Device Descriptor: > > bLength 18 > > bDescriptorType 1 > > bcdUSB 2.00 > > bDeviceClass 0 (Defined at Interface level) > > bDeviceSubClass 0 > > bDeviceProtocol 0 > > bMaxPacketSize0 8 > > idVendor 0x2304 Pinnacle Systems, Inc. > > idProduct 0x0225 Remote Kit Infrared Transceiver > > bcdDevice 0.01 > > iManufacturer 1 Pinnacle Systems > > iProduct 2 PCTV Remote USB > > iSerial 5 7FFFFFFFFFFFFFFF > > bNumConfigurations 1 > > Configuration Descriptor: > > bLength 9 > > bDescriptorType 2 > > wTotalLength 32 > > bNumInterfaces 1 > > bConfigurationValue 1 > > iConfiguration 3 StandardConfiguration > > bmAttributes 0xa0 > > (Bus Powered) > > Remote Wakeup > > MaxPower 100mA > > Interface Descriptor: > > bLength 9 > > bDescriptorType 4 > > bInterfaceNumber 0 > > bAlternateSetting 0 > > bNumEndpoints 2 > > bInterfaceClass 255 Vendor Specific Class > > bInterfaceSubClass 0 > > bInterfaceProtocol 0 > > iInterface 4 StandardInterface > > Endpoint Descriptor: > > bLength 7 > > bDescriptorType 5 > > bEndpointAddress 0x81 EP 1 IN > > bmAttributes 2 > > Transfer Type Bulk > > Synch Type None > > Usage Type Data > > wMaxPacketSize 0x0040 1x 64 bytes > > bInterval 10 > > Hmm... interval is equal to 10, e. g. 125us * 2^(10 - 1) = 64 ms. > > I'm wandering why mceusb is just forcing the interval to 1 (125ms). That > sounds wrong, except, of course, if the endpoint descriptor is wrong.
Note that the endpoint descriptor describes it as a bulk endpoint, but it is used as a interrupt endpoint by the driver. For bulk endpoints, the interval should not be used (?). Maybe the correct solution would be to use the endpoints as bulk endpoints if that is what the endpoint says? mceusb devices come in interrupt and bulk flavours. > On my eyes, though, 64ms seems to be a good enough interval to get > those events. Each packet will be 64 bytes, and at 64 ms you should be able to 960 bytes per second. That's more than enough. > Jarod/Sean, > > Are there any good reason for the mceusb driver to do this? > ep_in->bInterval = 1; > ep_out->bInterval = 1; I don't know. > At least on my tests here with audio with xHCI and EHCI with audio on > em28xx, it seems that EHCI just uses the USB endpoint interval, when > urb->interval == 1, while xHCI uses whatever value stored there. The xhci driver is not happy about the interval being changed. With CONFIG_USB_DEBUG you get: usb 3-12: Driver uses different interval (8 microframes) than xHCI (1 microframe) Sean -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
