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Message-ID: <20140430230424.GA5880@xanatos>
Date: Wed, 30 Apr 2014 16:04:24 -0700
From: Sarah Sharp <sarah.a.sharp@...ux.intel.com>
To: Julius Werner <jwerner@...omium.org>
Cc: Mathias Nyman <mathias.nyman@...ux.intel.com>,
Alan Stern <stern@...land.harvard.edu>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Vincent Palatin <vpalatin@...omium.org>,
Andrew Bresticker <abrestic@...omium.org>,
Jim Lin <jilin@...dia.com>, linux-usb@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] usb: xhci: Correct last context entry calculation for
Configure Endpoint
Hi Mathias,
I tested both this patch and your global command queue patches on top of
your for-usb-linus branch. After reverting commit 400362f1d8dc "ALSA:
usb-audio: Resume mixer values properly", I was able to get my USB
webcam working. [1]
I wrote a small shell script (attached) to start and kill guvcview over
and over, so that I could test the xHCI driver issuing Configure
Endpoint commands, and proceeded to plug and unplug a VIA USB 3.0 hub in
over and over again. I got occasional descriptor fetch errors and once
saw a Set Address timeout, and everything seemed to work as expected.
In short, I think it's fine to merge Julius' patch to usb-linus and your
command queue patches to usb-next.
Sarah Sharp
[1] https://lkml.org/lkml/2014/4/19/117
On Tue, Apr 29, 2014 at 10:38:17AM -0700, Julius Werner wrote:
> The current XHCI driver recalculates the Context Entries field in the
> Slot Context on every add_endpoint() and drop_endpoint() call. In the
> case of drop_endpoint(), it seems to assume that the add_flags will
> always contain every endpoint for the new configuration, which is not
> necessarily correct if you don't make assumptions about how the USB core
> uses the add_endpoint/drop_endpoint interface (add_flags only contains
> endpoints that are new additions in the new configuration).
>
> Furthermore, EP0_FLAG is not consistently set in add_flags throughout
> the lifetime of a device. This means that when all endpoints are
> dropped, the Context Entries field can be set to 0 (which is invalid and
> may cause a Parameter Error) or -1 (which is interpreted as 31 and
> causes the driver to keep using the old, incorrect value).
>
> The only surefire way to set this field right is to also take all
> existing endpoints into account, and to force the value to 1 (meaning
> only EP0 is active) if no other endpoint is found. This patch implements
> that as a single step in the final check_bandwidth() call and removes
> the intermediary calculations from add_endpoint() and drop_endpoint().
>
> Signed-off-by: Julius Werner <jwerner@...omium.org>
> ---
> drivers/usb/host/xhci.c | 51 +++++++++++++++++--------------------------------
> 1 file changed, 18 insertions(+), 33 deletions(-)
>
> diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
> index 924a6cc..fec6423 100644
> --- a/drivers/usb/host/xhci.c
> +++ b/drivers/usb/host/xhci.c
> @@ -1562,12 +1562,10 @@ int xhci_drop_endpoint(struct usb_hcd *hcd, struct usb_device *udev,
> struct xhci_hcd *xhci;
> struct xhci_container_ctx *in_ctx, *out_ctx;
> struct xhci_input_control_ctx *ctrl_ctx;
> - struct xhci_slot_ctx *slot_ctx;
> - unsigned int last_ctx;
> unsigned int ep_index;
> struct xhci_ep_ctx *ep_ctx;
> u32 drop_flag;
> - u32 new_add_flags, new_drop_flags, new_slot_info;
> + u32 new_add_flags, new_drop_flags;
> int ret;
>
> ret = xhci_check_args(hcd, udev, ep, 1, true, __func__);
> @@ -1614,24 +1612,13 @@ int xhci_drop_endpoint(struct usb_hcd *hcd, struct usb_device *udev,
> ctrl_ctx->add_flags &= cpu_to_le32(~drop_flag);
> new_add_flags = le32_to_cpu(ctrl_ctx->add_flags);
>
> - last_ctx = xhci_last_valid_endpoint(le32_to_cpu(ctrl_ctx->add_flags));
> - slot_ctx = xhci_get_slot_ctx(xhci, in_ctx);
> - /* Update the last valid endpoint context, if we deleted the last one */
> - if ((le32_to_cpu(slot_ctx->dev_info) & LAST_CTX_MASK) >
> - LAST_CTX(last_ctx)) {
> - slot_ctx->dev_info &= cpu_to_le32(~LAST_CTX_MASK);
> - slot_ctx->dev_info |= cpu_to_le32(LAST_CTX(last_ctx));
> - }
> - new_slot_info = le32_to_cpu(slot_ctx->dev_info);
> -
> xhci_endpoint_zero(xhci, xhci->devs[udev->slot_id], ep);
>
> - xhci_dbg(xhci, "drop ep 0x%x, slot id %d, new drop flags = %#x, new add flags = %#x, new slot info = %#x\n",
> + xhci_dbg(xhci, "drop ep 0x%x, slot id %d, new drop flags = %#x, new add flags = %#x\n",
> (unsigned int) ep->desc.bEndpointAddress,
> udev->slot_id,
> (unsigned int) new_drop_flags,
> - (unsigned int) new_add_flags,
> - (unsigned int) new_slot_info);
> + (unsigned int) new_add_flags);
> return 0;
> }
>
> @@ -1654,11 +1641,9 @@ int xhci_add_endpoint(struct usb_hcd *hcd, struct usb_device *udev,
> struct xhci_hcd *xhci;
> struct xhci_container_ctx *in_ctx, *out_ctx;
> unsigned int ep_index;
> - struct xhci_slot_ctx *slot_ctx;
> struct xhci_input_control_ctx *ctrl_ctx;
> u32 added_ctxs;
> - unsigned int last_ctx;
> - u32 new_add_flags, new_drop_flags, new_slot_info;
> + u32 new_add_flags, new_drop_flags;
> struct xhci_virt_device *virt_dev;
> int ret = 0;
>
> @@ -1673,7 +1658,6 @@ int xhci_add_endpoint(struct usb_hcd *hcd, struct usb_device *udev,
> return -ENODEV;
>
> added_ctxs = xhci_get_endpoint_flag(&ep->desc);
> - last_ctx = xhci_last_valid_endpoint(added_ctxs);
> if (added_ctxs == SLOT_FLAG || added_ctxs == EP0_FLAG) {
> /* FIXME when we have to issue an evaluate endpoint command to
> * deal with ep0 max packet size changing once we get the
> @@ -1739,24 +1723,14 @@ int xhci_add_endpoint(struct usb_hcd *hcd, struct usb_device *udev,
> */
> new_drop_flags = le32_to_cpu(ctrl_ctx->drop_flags);
>
> - slot_ctx = xhci_get_slot_ctx(xhci, in_ctx);
> - /* Update the last valid endpoint context, if we just added one past */
> - if ((le32_to_cpu(slot_ctx->dev_info) & LAST_CTX_MASK) <
> - LAST_CTX(last_ctx)) {
> - slot_ctx->dev_info &= cpu_to_le32(~LAST_CTX_MASK);
> - slot_ctx->dev_info |= cpu_to_le32(LAST_CTX(last_ctx));
> - }
> - new_slot_info = le32_to_cpu(slot_ctx->dev_info);
> -
> /* Store the usb_device pointer for later use */
> ep->hcpriv = udev;
>
> - xhci_dbg(xhci, "add ep 0x%x, slot id %d, new drop flags = %#x, new add flags = %#x, new slot info = %#x\n",
> + xhci_dbg(xhci, "add ep 0x%x, slot id %d, new drop flags = %#x, new add flags = %#x\n",
> (unsigned int) ep->desc.bEndpointAddress,
> udev->slot_id,
> (unsigned int) new_drop_flags,
> - (unsigned int) new_add_flags,
> - (unsigned int) new_slot_info);
> + (unsigned int) new_add_flags);
> return 0;
> }
>
> @@ -2723,8 +2697,19 @@ int xhci_check_bandwidth(struct usb_hcd *hcd, struct usb_device *udev)
> ctrl_ctx->drop_flags == 0)
> return 0;
>
> - xhci_dbg(xhci, "New Input Control Context:\n");
> + /* Fix up Context Entries field. Minimum value is EP0 == BIT(1). */
> slot_ctx = xhci_get_slot_ctx(xhci, virt_dev->in_ctx);
> + for (i = 31; i >= 1; i--) {
> + __le32 le32 = cpu_to_le32(BIT(i));
> + if ((virt_dev->eps[i-1].ring && !(ctrl_ctx->drop_flags & le32))
> + || (ctrl_ctx->add_flags & le32) || i == 1) {
> + slot_ctx->dev_info &= cpu_to_le32(~LAST_CTX_MASK);
> + slot_ctx->dev_info |= cpu_to_le32(LAST_CTX(i));
> + break;
> + }
> + }
> +
> + xhci_dbg(xhci, "New Input Control Context:\n");
> xhci_dbg_ctx(xhci, virt_dev->in_ctx,
> LAST_CTX_TO_EP_NUM(le32_to_cpu(slot_ctx->dev_info)));
>
> --
> 1.8.3.2
>
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