From e4f47e3675e6f1f40906b785b934ce963e9f2eb3 Mon Sep 17 00:00:00 2001 From: Alan Stern Date: Wed, 8 May 2013 11:18:05 -0400 Subject: [PATCH] USB: xHCI: override bogus bulk wMaxPacketSize values MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit This patch shortens the logic in xhci_endpoint_init() by moving common calculations involving max_packet and max_burst outside the switch statement, rather than repeating the same code in multiple case-specific statements. It also replaces two usages of max_packet which were clearly intended to be max_burst all along. More importantly, it compensates for a common bug in high-speed bulk endpoint descriptors. In many devices there is a bulk endpoint having a wMaxPacketSize value smaller than 512, which is forbidden by the USB spec. Some xHCI controllers can't handle this and refuse to accept the endpoint. This patch changes the max_packet value to 512, which allows the controller to use the endpoint properly. In practice the bogus maxpacket size doesn't matter, because none of the transfers sent via these endpoints are longer than the maxpacket value anyway. Signed-off-by: Alan Stern Reported-and-tested-by: "Aurélien Leblond" CC: Signed-off-by: Greg Kroah-Hartman --- drivers/usb/host/xhci-mem.c | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-) diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c index 965b539bc474..2cfc465925bd 100644 --- a/drivers/usb/host/xhci-mem.c +++ b/drivers/usb/host/xhci-mem.c @@ -1423,15 +1423,17 @@ int xhci_endpoint_init(struct xhci_hcd *xhci, ep_ctx->ep_info2 |= cpu_to_le32(xhci_get_endpoint_type(udev, ep)); /* Set the max packet size and max burst */ + max_packet = GET_MAX_PACKET(usb_endpoint_maxp(&ep->desc)); + max_burst = 0; switch (udev->speed) { case USB_SPEED_SUPER: - max_packet = usb_endpoint_maxp(&ep->desc); - ep_ctx->ep_info2 |= cpu_to_le32(MAX_PACKET(max_packet)); /* dig out max burst from ep companion desc */ - max_packet = ep->ss_ep_comp.bMaxBurst; - ep_ctx->ep_info2 |= cpu_to_le32(MAX_BURST(max_packet)); + max_burst = ep->ss_ep_comp.bMaxBurst; break; case USB_SPEED_HIGH: + /* Some devices get this wrong */ + if (usb_endpoint_xfer_bulk(&ep->desc)) + max_packet = 512; /* bits 11:12 specify the number of additional transaction * opportunities per microframe (USB 2.0, section 9.6.6) */ @@ -1439,17 +1441,16 @@ int xhci_endpoint_init(struct xhci_hcd *xhci, usb_endpoint_xfer_int(&ep->desc)) { max_burst = (usb_endpoint_maxp(&ep->desc) & 0x1800) >> 11; - ep_ctx->ep_info2 |= cpu_to_le32(MAX_BURST(max_burst)); } - /* Fall through */ + break; case USB_SPEED_FULL: case USB_SPEED_LOW: - max_packet = GET_MAX_PACKET(usb_endpoint_maxp(&ep->desc)); - ep_ctx->ep_info2 |= cpu_to_le32(MAX_PACKET(max_packet)); break; default: BUG(); } + ep_ctx->ep_info2 |= cpu_to_le32(MAX_PACKET(max_packet) | + MAX_BURST(max_burst)); max_esit_payload = xhci_get_max_esit_payload(xhci, udev, ep); ep_ctx->tx_info = cpu_to_le32(MAX_ESIT_PAYLOAD_FOR_EP(max_esit_payload)); -- 2.39.5