Commit a73d9d9c authored Jun 24, 2020 by Al Cooper Committed by Greg Kroah-Hartman Jun 24, 2020

xhci: Fix enumeration issue when setting max packet size for FS devices.



Unable to complete the enumeration of a USB TV Tuner device.

Per XHCI spec (4.6.5), the EP state field of the input context shall
be cleared for a set address command. In the special case of an FS
device that has "MaxPacketSize0 = 8", the Linux XHCI driver does
not do this before evaluating the context. With an XHCI controller
that checks the EP state field for parameter context error this
causes a problem in cases such as the device getting reset again
after enumeration.

When that field is cleared, the problem does not occur.

This was found and fixed by Sasi Kumar.

Cc: stable@vger.kernel.org
Signed-off-by: Al Cooper <alcooperx@gmail.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20200624135949.22611-3-mathias.nyman@linux.intel.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent dceea670

drivers/usb/host/xhci.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -1430,6 +1430,7 @@ static int xhci_check_maxpacket(struct xhci_hcd *xhci, unsigned int slot_id,
		xhci->devs[slot_id]->out_ctx, ep_index);

		ep_ctx = xhci_get_ep_ctx(xhci, command->in_ctx, ep_index);
		ep_ctx->ep_info &= cpu_to_le32(~EP_STATE_MASK);/* must clear */
		ep_ctx->ep_info2 &= cpu_to_le32(~MAX_PACKET_MASK);
		ep_ctx->ep_info2 \|= cpu_to_le32(MAX_PACKET(max_packet_size));

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