Hi, I'm working on a project to support USB headset on a device containing TI chipset DM8168 SoC. It runs Linux kernel version 2.6.37. The headset works fine with proper audio when connected to USB 2.0 ports which uses musb host controller driver. However, when I connect the headset to USB 3.0 ports, which use xhci host controller driver, it sometimes throws the following error repeatedly. --- xhci_hcd 0000:09:00.0: ERROR Transfer event TRB DMA ptr not part of current TD --- After this error, most of the PCM read/writes fail and xhci starts throwing other "ep ring" errors as shown below. --- cannot submit datapipe for urb 2, error -22: internal error xhci_hcd 0000:09:00.0: ERROR Transfer event TRB DMA ptr not part of current TD cannot submit datapipe for urb 2, error -22: internal error xhci_hcd 0000:09:00.0: ERROR Transfer event TRB DMA ptr not part of current TD cannot submit datapipe for urb 2, error -22: internal error xhci_hcd 0000:09:00.0: ERROR Transfer event TRB DMA ptr not part of current TD cannot submit datapipe for urb 2, error -22: internal error xhci_hcd 0000:09:00.0: ERROR Transfer event TRB DMA ptr not part of current TD cannot submit datapipe for urb 2, error -22: internal error xhci_hcd 0000:09:00.0: ERROR Transfer event TRB DMA ptr not part of current TD xhci_hcd 0000:09:00.0: ERROR Transfer event TRB DMA ptr not part of current TD xhci_hcd 0000:09:00.0: ERROR Transfer event TRB DMA ptr not part of current TD xhci_hcd 0000:09:00.0: ERROR no room on ep ring cannot submit datapipe for urb 0, error -12: unknown error xhci_hcd 0000:09:00.0: ERROR no room on ep ring cannot submit datapipe for urb 0, error -12: unknown error xhci_hcd 0000:09:00.0: ERROR no room on ep ring --- I suspect this could be a bug fixed by the patch titled "xhci: Fix bug after deq ptr set to link TRB" which was submitted to kernel in v3.6. Commit id is 50d0206fcaea3e736f912fd5b00ec6233fb4ce44. In the commit message of this patch, it is mentioned that this fix has to be backported to kernels as old as 2.6.31 and a separate patch will be created for older kernels. Following is the excerpt from the commit message of this patch: --- This patch should be backported to kernels as old as 2.6.31. A separate patch will be created for kernels older than 3.4, since inc_deq was modified in 3.4 and this patch will not apply. --- Please let me know if a patch is available for this fix which can be applied to kernel 2.6.37. Appreciate your help on this. Thanks, Goutham BG -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
