Re: [PATCH v3 1/2] drivers: usb/core/urb: Add URB_FREE_COHERENT

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 




On 22.06.22 12:03, David Laight wrote:
> Yes, being able to do short transfers from buffer space in the urb
> would save all the issues about having to allocate an extra
> buffer to avoid DMA from stack.

That is just as hard to do for DMA coherency.

> Indeed for XHCI there is a bit that allows 8 bytes of data to
> replace the pointer in the ring structure itself.
> I don't remember the driver every doing that.

XHCI does use it. There was even a bug with endianness.

	Regards
		Oliver




[Index of Archives]     [Linux Media]     [Linux Input]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]     [Old Linux USB Devel Archive]

  Powered by Linux