This is a note to let you know that I've just added the patch titled xhci: Fix enumeration issue when setting max packet size for FS devices. to the 4.19-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: xhci-fix-enumeration-issue-when-setting-max-packet-size-for-fs-devices.patch and it can be found in the queue-4.19 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From a73d9d9cfc3cfceabd91fb0b0c13e4062b6dbcd7 Mon Sep 17 00:00:00 2001 From: Al Cooper <alcooperx@xxxxxxxxx> Date: Wed, 24 Jun 2020 16:59:46 +0300 Subject: xhci: Fix enumeration issue when setting max packet size for FS devices. From: Al Cooper <alcooperx@xxxxxxxxx> commit a73d9d9cfc3cfceabd91fb0b0c13e4062b6dbcd7 upstream. 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@xxxxxxxxxxxxxxx Signed-off-by: Al Cooper <alcooperx@xxxxxxxxx> Signed-off-by: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20200624135949.22611-3-mathias.nyman@xxxxxxxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/usb/host/xhci.c | 1 + 1 file changed, 1 insertion(+) --- a/drivers/usb/host/xhci.c +++ b/drivers/usb/host/xhci.c @@ -1405,6 +1405,7 @@ static int xhci_check_maxpacket(struct x 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)); Patches currently in stable-queue which might be from alcooperx@xxxxxxxxx are queue-4.19/xhci-fix-enumeration-issue-when-setting-max-packet-size-for-fs-devices.patch