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* [PATCH v3 1/1] usb: xhci: Add Clear_TT_Buffer
@ 2019-04-30  3:06 ` Jim Lin
  0 siblings, 0 replies; 6+ messages in thread
From: Jim Lin @ 2019-04-30  3:06 UTC (permalink / raw)
  To: mathias.nyman, gregkh; +Cc: linux-usb, linux-kernel, Jim Lin

USB 2.0 specification chapter 11.17.5 says "as part of endpoint halt
processing for full-/low-speed endpoints connected via a TT, the host
software must use the Clear_TT_Buffer request to the TT to ensure
that the buffer is not in the busy state".

In our case, a full-speed speaker (ConferenceCam) is behind a high-
speed hub (ConferenceCam Connect), sometimes once we get STALL on a
request we may continue to get STALL with the folllowing requests,
like Set_Interface.

Here we add Clear_TT_Buffer for the following Set_Interface requests
to get ACK successfully.

Signed-off-by: Jim Lin <jilin@nvidia.com>
---
v2: xhci_clear_tt_buffer_complete: add static, shorter indentation
    , remove its claiming in xhci.h
v3: Add description for clearing_tt (xhci.h)

 drivers/usb/host/xhci-ring.c | 28 ++++++++++++++++++++++++++++
 drivers/usb/host/xhci.c      |  7 +++++++
 drivers/usb/host/xhci.h      |  2 ++
 3 files changed, 37 insertions(+)

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 9215a28dad40..02b1ebad81e7 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -1786,6 +1786,33 @@ struct xhci_segment *trb_in_td(struct xhci_hcd *xhci,
 	return NULL;
 }
 
+static void xhci_clear_hub_tt_buffer(struct xhci_hcd *xhci,
+	unsigned int slot_id, struct xhci_td *td)
+{
+	struct xhci_virt_device *dev;
+	struct xhci_slot_ctx *slot_ctx;
+	int saved_devnum;
+
+	/*
+	 * As part of low/full-speed endpoint-halt processing
+	 * we must clear the TT buffer (USB 2.0 specification 11.17.5).
+	 */
+	if (td->urb->dev->tt && !usb_pipeint(td->urb->pipe) &&
+	    (td->urb->dev->tt->hub != xhci_to_hcd(xhci)->self.root_hub) &&
+	    !xhci->clearing_tt) {
+		xhci->clearing_tt = 1;
+		dev = xhci->devs[slot_id];
+		slot_ctx = xhci_get_slot_ctx(xhci, dev->out_ctx);
+		/* Update devnum temporarily for usb_hub_clear_tt_buffer */
+		saved_devnum = td->urb->dev->devnum;
+		td->urb->dev->devnum = (int) le32_to_cpu(slot_ctx->dev_state) &
+			DEV_ADDR_MASK;
+		if (usb_hub_clear_tt_buffer(td->urb))
+			xhci->clearing_tt = 0;
+		td->urb->dev->devnum = saved_devnum;
+	}
+}
+
 static void xhci_cleanup_halted_endpoint(struct xhci_hcd *xhci,
 		unsigned int slot_id, unsigned int ep_index,
 		unsigned int stream_id, struct xhci_td *td,
@@ -1804,6 +1831,7 @@ static void xhci_cleanup_halted_endpoint(struct xhci_hcd *xhci,
 	if (reset_type == EP_HARD_RESET) {
 		ep->ep_state |= EP_HARD_CLEAR_TOGGLE;
 		xhci_cleanup_stalled_ring(xhci, ep_index, stream_id, td);
+		xhci_clear_hub_tt_buffer(xhci, slot_id, td);
 	}
 	xhci_ring_cmd_db(xhci);
 }
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 7fa58c99f126..4890c3518aa3 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -5132,6 +5132,12 @@ int xhci_gen_setup(struct usb_hcd *hcd, xhci_get_quirks_t get_quirks)
 }
 EXPORT_SYMBOL_GPL(xhci_gen_setup);
 
+static void xhci_clear_tt_buffer_complete(struct usb_hcd *hcd,
+		struct usb_host_endpoint *ep)
+{
+	hcd_to_xhci(hcd)->clearing_tt = 0;
+}
+
 static const struct hc_driver xhci_hc_driver = {
 	.description =		"xhci-hcd",
 	.product_desc =		"xHCI Host Controller",
@@ -5192,6 +5198,7 @@ static const struct hc_driver xhci_hc_driver = {
 	.enable_usb3_lpm_timeout =	xhci_enable_usb3_lpm_timeout,
 	.disable_usb3_lpm_timeout =	xhci_disable_usb3_lpm_timeout,
 	.find_raw_port_number =	xhci_find_raw_port_number,
+	.clear_tt_buffer_complete = xhci_clear_tt_buffer_complete,
 };
 
 void xhci_init_driver(struct hc_driver *drv,
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index 9334cdee382a..dab1476e5bdf 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1864,6 +1864,8 @@ struct xhci_hcd {
 	unsigned		hw_lpm_support:1;
 	/* Broken Suspend flag for SNPS Suspend resume issue */
 	unsigned		broken_suspend:1;
+	/* Clear_TT_Buffer in progress */
+	unsigned		clearing_tt:1;
 	/* cached usb2 extened protocol capabilites */
 	u32                     *ext_caps;
 	unsigned int            num_ext_caps;
-- 
2.1.4


^ permalink raw reply related	[flat|nested] 6+ messages in thread

* [v3,1/1] usb: xhci: Add Clear_TT_Buffer
@ 2019-04-30  3:06 ` Jim Lin
  0 siblings, 0 replies; 6+ messages in thread
From: Jim Lin @ 2019-04-30  3:06 UTC (permalink / raw)
  To: mathias.nyman, gregkh; +Cc: linux-usb, linux-kernel, Jim Lin

USB 2.0 specification chapter 11.17.5 says "as part of endpoint halt
processing for full-/low-speed endpoints connected via a TT, the host
software must use the Clear_TT_Buffer request to the TT to ensure
that the buffer is not in the busy state".

In our case, a full-speed speaker (ConferenceCam) is behind a high-
speed hub (ConferenceCam Connect), sometimes once we get STALL on a
request we may continue to get STALL with the folllowing requests,
like Set_Interface.

Here we add Clear_TT_Buffer for the following Set_Interface requests
to get ACK successfully.

Signed-off-by: Jim Lin <jilin@nvidia.com>
---
v2: xhci_clear_tt_buffer_complete: add static, shorter indentation
    , remove its claiming in xhci.h
v3: Add description for clearing_tt (xhci.h)

 drivers/usb/host/xhci-ring.c | 28 ++++++++++++++++++++++++++++
 drivers/usb/host/xhci.c      |  7 +++++++
 drivers/usb/host/xhci.h      |  2 ++
 3 files changed, 37 insertions(+)

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 9215a28dad40..02b1ebad81e7 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -1786,6 +1786,33 @@ struct xhci_segment *trb_in_td(struct xhci_hcd *xhci,
 	return NULL;
 }
 
+static void xhci_clear_hub_tt_buffer(struct xhci_hcd *xhci,
+	unsigned int slot_id, struct xhci_td *td)
+{
+	struct xhci_virt_device *dev;
+	struct xhci_slot_ctx *slot_ctx;
+	int saved_devnum;
+
+	/*
+	 * As part of low/full-speed endpoint-halt processing
+	 * we must clear the TT buffer (USB 2.0 specification 11.17.5).
+	 */
+	if (td->urb->dev->tt && !usb_pipeint(td->urb->pipe) &&
+	    (td->urb->dev->tt->hub != xhci_to_hcd(xhci)->self.root_hub) &&
+	    !xhci->clearing_tt) {
+		xhci->clearing_tt = 1;
+		dev = xhci->devs[slot_id];
+		slot_ctx = xhci_get_slot_ctx(xhci, dev->out_ctx);
+		/* Update devnum temporarily for usb_hub_clear_tt_buffer */
+		saved_devnum = td->urb->dev->devnum;
+		td->urb->dev->devnum = (int) le32_to_cpu(slot_ctx->dev_state) &
+			DEV_ADDR_MASK;
+		if (usb_hub_clear_tt_buffer(td->urb))
+			xhci->clearing_tt = 0;
+		td->urb->dev->devnum = saved_devnum;
+	}
+}
+
 static void xhci_cleanup_halted_endpoint(struct xhci_hcd *xhci,
 		unsigned int slot_id, unsigned int ep_index,
 		unsigned int stream_id, struct xhci_td *td,
@@ -1804,6 +1831,7 @@ static void xhci_cleanup_halted_endpoint(struct xhci_hcd *xhci,
 	if (reset_type == EP_HARD_RESET) {
 		ep->ep_state |= EP_HARD_CLEAR_TOGGLE;
 		xhci_cleanup_stalled_ring(xhci, ep_index, stream_id, td);
+		xhci_clear_hub_tt_buffer(xhci, slot_id, td);
 	}
 	xhci_ring_cmd_db(xhci);
 }
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 7fa58c99f126..4890c3518aa3 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -5132,6 +5132,12 @@ int xhci_gen_setup(struct usb_hcd *hcd, xhci_get_quirks_t get_quirks)
 }
 EXPORT_SYMBOL_GPL(xhci_gen_setup);
 
+static void xhci_clear_tt_buffer_complete(struct usb_hcd *hcd,
+		struct usb_host_endpoint *ep)
+{
+	hcd_to_xhci(hcd)->clearing_tt = 0;
+}
+
 static const struct hc_driver xhci_hc_driver = {
 	.description =		"xhci-hcd",
 	.product_desc =		"xHCI Host Controller",
@@ -5192,6 +5198,7 @@ static const struct hc_driver xhci_hc_driver = {
 	.enable_usb3_lpm_timeout =	xhci_enable_usb3_lpm_timeout,
 	.disable_usb3_lpm_timeout =	xhci_disable_usb3_lpm_timeout,
 	.find_raw_port_number =	xhci_find_raw_port_number,
+	.clear_tt_buffer_complete = xhci_clear_tt_buffer_complete,
 };
 
 void xhci_init_driver(struct hc_driver *drv,
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index 9334cdee382a..dab1476e5bdf 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1864,6 +1864,8 @@ struct xhci_hcd {
 	unsigned		hw_lpm_support:1;
 	/* Broken Suspend flag for SNPS Suspend resume issue */
 	unsigned		broken_suspend:1;
+	/* Clear_TT_Buffer in progress */
+	unsigned		clearing_tt:1;
 	/* cached usb2 extened protocol capabilites */
 	u32                     *ext_caps;
 	unsigned int            num_ext_caps;

^ permalink raw reply related	[flat|nested] 6+ messages in thread

* Re: [PATCH v3 1/1] usb: xhci: Add Clear_TT_Buffer
@ 2019-05-02 10:56   ` Mathias Nyman
  0 siblings, 0 replies; 6+ messages in thread
From: Mathias Nyman @ 2019-05-02 10:56 UTC (permalink / raw)
  To: Jim Lin, mathias.nyman, gregkh; +Cc: linux-usb, linux-kernel, Alan Stern

On 30.4.2019 6.06, Jim Lin wrote:
> USB 2.0 specification chapter 11.17.5 says "as part of endpoint halt
> processing for full-/low-speed endpoints connected via a TT, the host
> software must use the Clear_TT_Buffer request to the TT to ensure
> that the buffer is not in the busy state".

Good point, xhci isn't making sure TT buffers get cleared when they should.

> 
> In our case, a full-speed speaker (ConferenceCam) is behind a high-
> speed hub (ConferenceCam Connect), sometimes once we get STALL on a
> request we may continue to get STALL with the folllowing requests,
> like Set_Interface.
> 
> Here we add Clear_TT_Buffer for the following Set_Interface requests
> to get ACK successfully.
> 
> Signed-off-by: Jim Lin <jilin@nvidia.com>
> ---
> v2: xhci_clear_tt_buffer_complete: add static, shorter indentation
>      , remove its claiming in xhci.h
> v3: Add description for clearing_tt (xhci.h)
> 
>   drivers/usb/host/xhci-ring.c | 28 ++++++++++++++++++++++++++++
>   drivers/usb/host/xhci.c      |  7 +++++++
>   drivers/usb/host/xhci.h      |  2 ++
>   3 files changed, 37 insertions(+)
> 
> diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
> index 9215a28dad40..02b1ebad81e7 100644
> --- a/drivers/usb/host/xhci-ring.c
> +++ b/drivers/usb/host/xhci-ring.c
> @@ -1786,6 +1786,33 @@ struct xhci_segment *trb_in_td(struct xhci_hcd *xhci,
>   	return NULL;
>   }
>   
> +static void xhci_clear_hub_tt_buffer(struct xhci_hcd *xhci,
> +	unsigned int slot_id, struct xhci_td *td)
> +{
> +	struct xhci_virt_device *dev;
> +	struct xhci_slot_ctx *slot_ctx;
> +	int saved_devnum;
> +
> +	/*
> +	 * As part of low/full-speed endpoint-halt processing
> +	 * we must clear the TT buffer (USB 2.0 specification 11.17.5).
> +	 */
> +	if (td->urb->dev->tt && !usb_pipeint(td->urb->pipe) &&
> +	    (td->urb->dev->tt->hub != xhci_to_hcd(xhci)->self.root_hub) &&
> +	    !xhci->clearing_tt) {
> +		xhci->clearing_tt = 1;

one xhci->clearing_tt under is not enough, there might be several HS hubs, or
multi TT hubs with halted endpoints at the same time that need TT clearing.

How about a flag per endpoint?

For example Aadding a EP_CLEARING_TT flag for ep_state in struct xhci_virt_ep?
just like EP_STOP_CMD_PENDING, or EP_HALTED

> +		dev = xhci->devs[slot_id];
> +		slot_ctx = xhci_get_slot_ctx(xhci, dev->out_ctx);
> +		/* Update devnum temporarily for usb_hub_clear_tt_buffer */
> +		saved_devnum = td->urb->dev->devnum;
> +		td->urb->dev->devnum = (int) le32_to_cpu(slot_ctx->dev_state) &
> +			DEV_ADDR_MASK;

Changing the struct usb_device devnum on the fly seems like a bit of a hack, and probably
causes issues elsewhere. Devnum is tied to uevents, usbfs, sysfs etc.

We need another solution, some options:

- Let usb_hub_clear_tt_buffer() figure out address and not just use devnum if host == xhci.
- Add address to struct usb_device, (would have both address and devnum), use it when needed.
- Provide address as parameter to usb_clear_tt_buffer() (api change, changes other host drivers)
- Force devnum to be same as address, usb core can't choose address for xhci devices.

-Mathias

^ permalink raw reply	[flat|nested] 6+ messages in thread

* [v3,1/1] usb: xhci: Add Clear_TT_Buffer
@ 2019-05-02 10:56   ` Mathias Nyman
  0 siblings, 0 replies; 6+ messages in thread
From: Mathias Nyman @ 2019-05-02 10:56 UTC (permalink / raw)
  To: Jim Lin, mathias.nyman, gregkh; +Cc: linux-usb, linux-kernel, Alan Stern

On 30.4.2019 6.06, Jim Lin wrote:
> USB 2.0 specification chapter 11.17.5 says "as part of endpoint halt
> processing for full-/low-speed endpoints connected via a TT, the host
> software must use the Clear_TT_Buffer request to the TT to ensure
> that the buffer is not in the busy state".

Good point, xhci isn't making sure TT buffers get cleared when they should.

> 
> In our case, a full-speed speaker (ConferenceCam) is behind a high-
> speed hub (ConferenceCam Connect), sometimes once we get STALL on a
> request we may continue to get STALL with the folllowing requests,
> like Set_Interface.
> 
> Here we add Clear_TT_Buffer for the following Set_Interface requests
> to get ACK successfully.
> 
> Signed-off-by: Jim Lin <jilin@nvidia.com>
> ---
> v2: xhci_clear_tt_buffer_complete: add static, shorter indentation
>      , remove its claiming in xhci.h
> v3: Add description for clearing_tt (xhci.h)
> 
>   drivers/usb/host/xhci-ring.c | 28 ++++++++++++++++++++++++++++
>   drivers/usb/host/xhci.c      |  7 +++++++
>   drivers/usb/host/xhci.h      |  2 ++
>   3 files changed, 37 insertions(+)
> 
> diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
> index 9215a28dad40..02b1ebad81e7 100644
> --- a/drivers/usb/host/xhci-ring.c
> +++ b/drivers/usb/host/xhci-ring.c
> @@ -1786,6 +1786,33 @@ struct xhci_segment *trb_in_td(struct xhci_hcd *xhci,
>   	return NULL;
>   }
>   
> +static void xhci_clear_hub_tt_buffer(struct xhci_hcd *xhci,
> +	unsigned int slot_id, struct xhci_td *td)
> +{
> +	struct xhci_virt_device *dev;
> +	struct xhci_slot_ctx *slot_ctx;
> +	int saved_devnum;
> +
> +	/*
> +	 * As part of low/full-speed endpoint-halt processing
> +	 * we must clear the TT buffer (USB 2.0 specification 11.17.5).
> +	 */
> +	if (td->urb->dev->tt && !usb_pipeint(td->urb->pipe) &&
> +	    (td->urb->dev->tt->hub != xhci_to_hcd(xhci)->self.root_hub) &&
> +	    !xhci->clearing_tt) {
> +		xhci->clearing_tt = 1;

one xhci->clearing_tt under is not enough, there might be several HS hubs, or
multi TT hubs with halted endpoints at the same time that need TT clearing.

How about a flag per endpoint?

For example Aadding a EP_CLEARING_TT flag for ep_state in struct xhci_virt_ep?
just like EP_STOP_CMD_PENDING, or EP_HALTED

> +		dev = xhci->devs[slot_id];
> +		slot_ctx = xhci_get_slot_ctx(xhci, dev->out_ctx);
> +		/* Update devnum temporarily for usb_hub_clear_tt_buffer */
> +		saved_devnum = td->urb->dev->devnum;
> +		td->urb->dev->devnum = (int) le32_to_cpu(slot_ctx->dev_state) &
> +			DEV_ADDR_MASK;

Changing the struct usb_device devnum on the fly seems like a bit of a hack, and probably
causes issues elsewhere. Devnum is tied to uevents, usbfs, sysfs etc.

We need another solution, some options:

- Let usb_hub_clear_tt_buffer() figure out address and not just use devnum if host == xhci.
- Add address to struct usb_device, (would have both address and devnum), use it when needed.
- Provide address as parameter to usb_clear_tt_buffer() (api change, changes other host drivers)
- Force devnum to be same as address, usb core can't choose address for xhci devices.

-Mathias

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH v3 1/1] usb: xhci: Add Clear_TT_Buffer
@ 2019-05-02 12:32     ` Jim Lin
  0 siblings, 0 replies; 6+ messages in thread
From: Jim Lin @ 2019-05-02 12:32 UTC (permalink / raw)
  To: Mathias Nyman, mathias.nyman, gregkh; +Cc: linux-usb, linux-kernel, Alan Stern



On 2019年05月02日 18:56, Mathias Nyman wrote:
> On 30.4.2019 6.06, Jim Lin wrote:
>> USB 2.0 specification chapter 11.17.5 says "as part of endpoint halt
>> processing for full-/low-speed endpoints connected via a TT, the host
>> software must use the Clear_TT_Buffer request to the TT to ensure
>> that the buffer is not in the busy state".
>
> Good point, xhci isn't making sure TT buffers get cleared when they 
> should.
>
>>
>> In our case, a full-speed speaker (ConferenceCam) is behind a high-
>> speed hub (ConferenceCam Connect), sometimes once we get STALL on a
>> request we may continue to get STALL with the folllowing requests,
>> like Set_Interface.
>>
>> Here we add Clear_TT_Buffer for the following Set_Interface requests
>> to get ACK successfully.
>>
>> Signed-off-by: Jim Lin <jilin@nvidia.com>
>> ---
>> v2: xhci_clear_tt_buffer_complete: add static, shorter indentation
>>      , remove its claiming in xhci.h
>> v3: Add description for clearing_tt (xhci.h)
>>
>>   drivers/usb/host/xhci-ring.c | 28 ++++++++++++++++++++++++++++
>>   drivers/usb/host/xhci.c      |  7 +++++++
>>   drivers/usb/host/xhci.h      |  2 ++
>>   3 files changed, 37 insertions(+)
>>
>> diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
>> index 9215a28dad40..02b1ebad81e7 100644
>> --- a/drivers/usb/host/xhci-ring.c
>> +++ b/drivers/usb/host/xhci-ring.c
>> @@ -1786,6 +1786,33 @@ struct xhci_segment *trb_in_td(struct xhci_hcd 
>> *xhci,
>>       return NULL;
>>   }
>>   +static void xhci_clear_hub_tt_buffer(struct xhci_hcd *xhci,
>> +    unsigned int slot_id, struct xhci_td *td)
>> +{
>> +    struct xhci_virt_device *dev;
>> +    struct xhci_slot_ctx *slot_ctx;
>> +    int saved_devnum;
>> +
>> +    /*
>> +     * As part of low/full-speed endpoint-halt processing
>> +     * we must clear the TT buffer (USB 2.0 specification 11.17.5).
>> +     */
>> +    if (td->urb->dev->tt && !usb_pipeint(td->urb->pipe) &&
>> +        (td->urb->dev->tt->hub != xhci_to_hcd(xhci)->self.root_hub) &&
>> +        !xhci->clearing_tt) {
>> +        xhci->clearing_tt = 1;
>
> one xhci->clearing_tt under is not enough, there might be several HS 
> hubs, or
> multi TT hubs with halted endpoints at the same time that need TT 
> clearing.
>
> How about a flag per endpoint?
>
> For example Aadding a EP_CLEARING_TT flag for ep_state in struct 
> xhci_virt_ep?
> just like EP_STOP_CMD_PENDING, or EP_HALTED
>
>> +        dev = xhci->devs[slot_id];
>> +        slot_ctx = xhci_get_slot_ctx(xhci, dev->out_ctx);
>> +        /* Update devnum temporarily for usb_hub_clear_tt_buffer */
>> +        saved_devnum = td->urb->dev->devnum;
>> +        td->urb->dev->devnum = (int) le32_to_cpu(slot_ctx->dev_state) &
>> +            DEV_ADDR_MASK;
>
> Changing the struct usb_device devnum on the fly seems like a bit of a 
> hack, and probably
> causes issues elsewhere. Devnum is tied to uevents, usbfs, sysfs etc.
>
> We need another solution, some options:
>
> - Let usb_hub_clear_tt_buffer() figure out address and not just use 
> devnum if host == xhci.
> - Add address to struct usb_device, (would have both address and 
> devnum), use it when needed.
> - Provide address as parameter to usb_clear_tt_buffer() (api change, 
> changes other host drivers)
> - Force devnum to be same as address, usb core can't choose address 
> for xhci devices.
>
> -Mathias
Thanks for review. Will try.

--nvpublic

^ permalink raw reply	[flat|nested] 6+ messages in thread

* [v3,1/1] usb: xhci: Add Clear_TT_Buffer
@ 2019-05-02 12:32     ` Jim Lin
  0 siblings, 0 replies; 6+ messages in thread
From: Jim Lin @ 2019-05-02 12:32 UTC (permalink / raw)
  To: Mathias Nyman, mathias.nyman, gregkh; +Cc: linux-usb, linux-kernel, Alan Stern

On 2019年05月02日 18:56, Mathias Nyman wrote:
> On 30.4.2019 6.06, Jim Lin wrote:
>> USB 2.0 specification chapter 11.17.5 says "as part of endpoint halt
>> processing for full-/low-speed endpoints connected via a TT, the host
>> software must use the Clear_TT_Buffer request to the TT to ensure
>> that the buffer is not in the busy state".
>
> Good point, xhci isn't making sure TT buffers get cleared when they 
> should.
>
>>
>> In our case, a full-speed speaker (ConferenceCam) is behind a high-
>> speed hub (ConferenceCam Connect), sometimes once we get STALL on a
>> request we may continue to get STALL with the folllowing requests,
>> like Set_Interface.
>>
>> Here we add Clear_TT_Buffer for the following Set_Interface requests
>> to get ACK successfully.
>>
>> Signed-off-by: Jim Lin <jilin@nvidia.com>
>> ---
>> v2: xhci_clear_tt_buffer_complete: add static, shorter indentation
>>      , remove its claiming in xhci.h
>> v3: Add description for clearing_tt (xhci.h)
>>
>>   drivers/usb/host/xhci-ring.c | 28 ++++++++++++++++++++++++++++
>>   drivers/usb/host/xhci.c      |  7 +++++++
>>   drivers/usb/host/xhci.h      |  2 ++
>>   3 files changed, 37 insertions(+)
>>
>> diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
>> index 9215a28dad40..02b1ebad81e7 100644
>> --- a/drivers/usb/host/xhci-ring.c
>> +++ b/drivers/usb/host/xhci-ring.c
>> @@ -1786,6 +1786,33 @@ struct xhci_segment *trb_in_td(struct xhci_hcd 
>> *xhci,
>>       return NULL;
>>   }
>>   +static void xhci_clear_hub_tt_buffer(struct xhci_hcd *xhci,
>> +    unsigned int slot_id, struct xhci_td *td)
>> +{
>> +    struct xhci_virt_device *dev;
>> +    struct xhci_slot_ctx *slot_ctx;
>> +    int saved_devnum;
>> +
>> +    /*
>> +     * As part of low/full-speed endpoint-halt processing
>> +     * we must clear the TT buffer (USB 2.0 specification 11.17.5).
>> +     */
>> +    if (td->urb->dev->tt && !usb_pipeint(td->urb->pipe) &&
>> +        (td->urb->dev->tt->hub != xhci_to_hcd(xhci)->self.root_hub) &&
>> +        !xhci->clearing_tt) {
>> +        xhci->clearing_tt = 1;
>
> one xhci->clearing_tt under is not enough, there might be several HS 
> hubs, or
> multi TT hubs with halted endpoints at the same time that need TT 
> clearing.
>
> How about a flag per endpoint?
>
> For example Aadding a EP_CLEARING_TT flag for ep_state in struct 
> xhci_virt_ep?
> just like EP_STOP_CMD_PENDING, or EP_HALTED
>
>> +        dev = xhci->devs[slot_id];
>> +        slot_ctx = xhci_get_slot_ctx(xhci, dev->out_ctx);
>> +        /* Update devnum temporarily for usb_hub_clear_tt_buffer */
>> +        saved_devnum = td->urb->dev->devnum;
>> +        td->urb->dev->devnum = (int) le32_to_cpu(slot_ctx->dev_state) &
>> +            DEV_ADDR_MASK;
>
> Changing the struct usb_device devnum on the fly seems like a bit of a 
> hack, and probably
> causes issues elsewhere. Devnum is tied to uevents, usbfs, sysfs etc.
>
> We need another solution, some options:
>
> - Let usb_hub_clear_tt_buffer() figure out address and not just use 
> devnum if host == xhci.
> - Add address to struct usb_device, (would have both address and 
> devnum), use it when needed.
> - Provide address as parameter to usb_clear_tt_buffer() (api change, 
> changes other host drivers)
> - Force devnum to be same as address, usb core can't choose address 
> for xhci devices.
>
> -Mathias
Thanks for review. Will try.

--nvpublic

^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2019-05-02 12:33 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-04-30  3:06 [PATCH v3 1/1] usb: xhci: Add Clear_TT_Buffer Jim Lin
2019-04-30  3:06 ` [v3,1/1] " Jim Lin
2019-05-02 10:56 ` [PATCH v3 1/1] " Mathias Nyman
2019-05-02 10:56   ` [v3,1/1] " Mathias Nyman
2019-05-02 12:32   ` [PATCH v3 1/1] " Jim Lin
2019-05-02 12:32     ` [v3,1/1] " Jim Lin

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