[PATCH v2 0/3] Rework "xhci: clear root port wake on bits if controller isn't wake-up capable"

[PATCH v2 0/3] Rework "xhci: clear root port wake on bits if controller isn't wake-up capable"

[Lu Baolu]

This serie of patch reworks commit ff8cbf250b448aac35589f6075082c3fcad8a8fe.
This has been discussed at http://www.spinics.net/lists/linux-usb/msg114986.html
It also includes a patch to fix a comment in drivers/usb/host/xhci.h.

Changes in v2:
* Should not be a quirk.
* Should be applied to all xhci controllers.

Lu Baolu (3):
  usb: xhci: Revert "xhci: clear root port wake on bits if controller
    isn't wake-up capable"
  usb: xhci: This reworks ff8cbf250b448aac35589f6075082c3fcad8a8fe
  usb: xhci: fix comment for PORT_DEV_REMOVE

 drivers/usb/host/xhci-hub.c |  5 +----
 drivers/usb/host/xhci-pci.c | 42 ++++++++++++++++++++++++++++++++++++++++++
 drivers/usb/host/xhci.h     |  8 +++++++-
 3 files changed, 50 insertions(+), 5 deletions(-)

-- 
1.9.1

[PATCH v2 1/3] usb: xhci: Revert "xhci: clear root port wake on bits if controller isn't wake-up capable"

[Lu Baolu]

This reverts commit ff8cbf250b448aac35589f6075082c3fcad8a8fe.

Commit ff8cbf250b448aac35589f6075082c3fcad8a8fe triggers the bug logged at

https://bugzilla.kernel.org/show_bug.cgi?id=85701

Reported-by: Dmitry Nezhevenko <dion@inhex.net>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
 drivers/usb/host/xhci-hub.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/usb/host/xhci-hub.c b/drivers/usb/host/xhci-hub.c
index 696160d..388cfd8 100644
--- a/drivers/usb/host/xhci-hub.c
+++ b/drivers/usb/host/xhci-hub.c
@@ -22,7 +22,6 @@
 
 
 #include <linux/slab.h>
-#include <linux/device.h>
 #include <asm/unaligned.h>
 
 #include "xhci.h"
@@ -1149,9 +1148,7 @@ int xhci_bus_suspend(struct usb_hcd *hcd)
 		 * including the USB 3.0 roothub, but only if CONFIG_PM_RUNTIME
 		 * is enabled, so also enable remote wake here.
 		 */
-		if (hcd->self.root_hub->do_remote_wakeup
-				&& device_may_wakeup(hcd->self.controller)) {
-
+		if (hcd->self.root_hub->do_remote_wakeup) {
 			if (t1 & PORT_CONNECT) {
 				t2 |= PORT_WKOC_E | PORT_WKDISC_E;
 				t2 &= ~PORT_WKCONN_E;
-- 
1.9.1

[PATCH v2 2/3] usb: xhci: This reworks ff8cbf250b448aac35589f6075082c3fcad8a8fe

[Lu Baolu]

xhci: clear root port wake on bits if controller isn't wake-up capable

When system is being suspended, if host device is not wakeup capable,
xhci_suspend() needs to clear all root port wake on bits.  Otherwise,
some platforms may generate spurious wakeup, even if PCI PME# is dis-
abled.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
 drivers/usb/host/xhci.c | 42 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)

diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 2a5d45b..cd57aae 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -35,6 +35,8 @@
 #define DRIVER_AUTHOR "Sarah Sharp"
 #define DRIVER_DESC "'eXtensible' Host Controller (xHC) Driver"
 
+#define	PORT_WAKE_BITS	(PORT_WKOC_E | PORT_WKDISC_E | PORT_WKCONN_E)
+
 /* Some 0.95 hardware can't handle the chain bit on a Link TRB being cleared */
 static int link_quirk;
 module_param(link_quirk, int, S_IRUGO | S_IWUSR);
@@ -851,6 +853,42 @@ static void xhci_clear_command_ring(struct xhci_hcd *xhci)
 	xhci_set_cmd_ring_deq(xhci);
 }
 
+static void xhci_disable_port_wake_on_bits(struct xhci_hcd *xhci)
+{
+	int port_index;
+	__le32 __iomem **port_array;
+	unsigned long flags;
+	u32 t1, t2;
+
+	spin_lock_irqsave(&xhci->lock, flags);
+
+	/* disble usb3 ports Wake bits*/
+	port_index = xhci->num_usb3_ports;
+	port_array = xhci->usb3_ports;
+	while (port_index--) {
+		t1 = readl(port_array[port_index]);
+		t2 = xhci_port_state_to_neutral(t1);
+		t2 &= ~PORT_WAKE_BITS;
+		t1 = xhci_port_state_to_neutral(t1);
+		if (t1 != t2)
+			writel(t2, port_array[port_index]);
+	}
+
+	/* disble usb2 ports Wake bits*/
+	port_index = xhci->num_usb2_ports;
+	port_array = xhci->usb2_ports;
+	while (port_index--) {
+		t1 = readl(port_array[port_index]);
+		t2 = xhci_port_state_to_neutral(t1);
+		t2 &= ~PORT_WAKE_BITS;
+		t1 = xhci_port_state_to_neutral(t1);
+		if (t1 != t2)
+			writel(t2, port_array[port_index]);
+	}
+
+	spin_unlock_irqrestore(&xhci->lock, flags);
+}
+
 /*
  * Stop HC (not bus-specific)
  *
@@ -868,6 +906,10 @@ int xhci_suspend(struct xhci_hcd *xhci)
 			xhci->shared_hcd->state != HC_STATE_SUSPENDED)
 		return -EINVAL;
 
+	/* Clear root port wake on bits if not wakeup capable. */
+	if (!device_may_wakeup(hcd->self.controller))
+		xhci_disable_port_wake_on_bits(xhci);
+
 	/* Don't poll the roothubs on bus suspend. */
 	xhci_dbg(xhci, "%s: stopping port polling.\n", __func__);
 	clear_bit(HCD_FLAG_POLL_RH, &hcd->flags);
-- 
1.9.1

[PATCH v2 3/3] usb: xhci: fix comment for PORT_DEV_REMOVE

[Lu Baolu]

According to xHCI specification, PORT_DEV_REMOVE(bit 30) in PORTSC
true means "Device is non-removable".

Reported-by: Juro Bystricky <jurobystricky@hotmail.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
 drivers/usb/host/xhci.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index df76d64..66c168a9 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -358,7 +358,7 @@ struct xhci_op_regs {
 /* wake on over-current (enable) */
 #define PORT_WKOC_E	(1 << 27)
 /* bits 28:29 reserved */
-/* true: device is removable - for USB 3.0 roothub emulation */
+/* true: device is non-removable - for USB 3.0 roothub emulation */
 #define PORT_DEV_REMOVE	(1 << 30)
 /* Initiate a warm port reset - complete when PORT_WRC is '1' */
 #define PORT_WR		(1 << 31)
-- 
1.9.1

Re: [PATCH v2 2/3] usb: xhci: This reworks ff8cbf250b448aac35589f6075082c3fcad8a8fe

[Alan Stern]

On Tue, 4 Nov 2014, Lu Baolu wrote:

> xhci: clear root port wake on bits if controller isn't wake-up capable
> 
> When system is being suspended, if host device is not wakeup capable,
> xhci_suspend() needs to clear all root port wake on bits.  Otherwise,
> some platforms may generate spurious wakeup, even if PCI PME# is dis-
> abled.
> 
> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
> ---
>  drivers/usb/host/xhci.c | 42 ++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 42 insertions(+)
> 
> diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
> index 2a5d45b..cd57aae 100644
> --- a/drivers/usb/host/xhci.c
> +++ b/drivers/usb/host/xhci.c
> @@ -35,6 +35,8 @@
>  #define DRIVER_AUTHOR "Sarah Sharp"
>  #define DRIVER_DESC "'eXtensible' Host Controller (xHC) Driver"
>  
> +#define	PORT_WAKE_BITS	(PORT_WKOC_E | PORT_WKDISC_E | PORT_WKCONN_E)
> +
>  /* Some 0.95 hardware can't handle the chain bit on a Link TRB being cleared */
>  static int link_quirk;
>  module_param(link_quirk, int, S_IRUGO | S_IWUSR);
> @@ -851,6 +853,42 @@ static void xhci_clear_command_ring(struct xhci_hcd *xhci)
>  	xhci_set_cmd_ring_deq(xhci);
>  }
>  
> +static void xhci_disable_port_wake_on_bits(struct xhci_hcd *xhci)
> +{
> +	int port_index;
> +	__le32 __iomem **port_array;
> +	unsigned long flags;
> +	u32 t1, t2;
> +
> +	spin_lock_irqsave(&xhci->lock, flags);
> +
> +	/* disble usb3 ports Wake bits*/
> +	port_index = xhci->num_usb3_ports;
> +	port_array = xhci->usb3_ports;
> +	while (port_index--) {
> +		t1 = readl(port_array[port_index]);
> +		t2 = xhci_port_state_to_neutral(t1);
> +		t2 &= ~PORT_WAKE_BITS;
> +		t1 = xhci_port_state_to_neutral(t1);
> +		if (t1 != t2)
> +			writel(t2, port_array[port_index]);
> +	}
> +
> +	/* disble usb2 ports Wake bits*/
> +	port_index = xhci->num_usb2_ports;
> +	port_array = xhci->usb2_ports;
> +	while (port_index--) {
> +		t1 = readl(port_array[port_index]);
> +		t2 = xhci_port_state_to_neutral(t1);
> +		t2 &= ~PORT_WAKE_BITS;
> +		t1 = xhci_port_state_to_neutral(t1);
> +		if (t1 != t2)
> +			writel(t2, port_array[port_index]);
> +	}
> +
> +	spin_unlock_irqrestore(&xhci->lock, flags);
> +}
> +
>  /*
>   * Stop HC (not bus-specific)
>   *
> @@ -868,6 +906,10 @@ int xhci_suspend(struct xhci_hcd *xhci)
>  			xhci->shared_hcd->state != HC_STATE_SUSPENDED)
>  		return -EINVAL;
>  
> +	/* Clear root port wake on bits if not wakeup capable. */
> +	if (!device_may_wakeup(hcd->self.controller))
> +		xhci_disable_port_wake_on_bits(xhci);
> +
>  	/* Don't poll the roothubs on bus suspend. */
>  	xhci_dbg(xhci, "%s: stopping port polling.\n", __func__);
>  	clear_bit(HCD_FLAG_POLL_RH, &hcd->flags);

This is better but still wrong.  Remember, this same code gets called
for system suspend _and_ for runtime suspend.  During runtime suspend,
wakeup is always supposed to be turned on, even if device_may_wakeup()
is false.  That's because device_may_wakeup() refers only to system
suspend.  What you need to test is the do_wakeup flag, which should be
passed into xhci_suspend() by xhci_pci_suspend() and
xhci_plat_suspend().

Another problem is in the patch description and the comments.  If 
device_may_wakeup() returns false, it doesn't mean the controller isn't 
wakeup-capable -- it means the controller isn't _allowed_ to wake up 
the system.  Those are two different things.

Finally, the code in xhci_disable_port_wake_on_bits() looks a little 
peculiar -- I'm not sure about all those calls to 
xhci_port_state_to_neutral().  But I'm not an expert on that; Mathias 
will have to advise on it.

Alan Stern

Re: [PATCH v2 2/3] usb: xhci: This reworks ff8cbf250b448aac35589f6075082c3fcad8a8fe

[Lu, Baolu]

On 11/5/2014 12:58 AM, Alan Stern wrote:
> On Tue, 4 Nov 2014, Lu Baolu wrote:
>
>> xhci: clear root port wake on bits if controller isn't wake-up capable
>>
>> When system is being suspended, if host device is not wakeup capable,
>> xhci_suspend() needs to clear all root port wake on bits.  Otherwise,
>> some platforms may generate spurious wakeup, even if PCI PME# is dis-
>> abled.
>>
>> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
>> ---
>>   drivers/usb/host/xhci.c | 42 ++++++++++++++++++++++++++++++++++++++++++
>>   1 file changed, 42 insertions(+)
>>
>> diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
>> index 2a5d45b..cd57aae 100644
>> --- a/drivers/usb/host/xhci.c
>> +++ b/drivers/usb/host/xhci.c
>> @@ -35,6 +35,8 @@
>>   #define DRIVER_AUTHOR "Sarah Sharp"
>>   #define DRIVER_DESC "'eXtensible' Host Controller (xHC) Driver"
>>   
>> +#define	PORT_WAKE_BITS	(PORT_WKOC_E | PORT_WKDISC_E | PORT_WKCONN_E)
>> +
>>   /* Some 0.95 hardware can't handle the chain bit on a Link TRB being cleared */
>>   static int link_quirk;
>>   module_param(link_quirk, int, S_IRUGO | S_IWUSR);
>> @@ -851,6 +853,42 @@ static void xhci_clear_command_ring(struct xhci_hcd *xhci)
>>   	xhci_set_cmd_ring_deq(xhci);
>>   }
>>   
>> +static void xhci_disable_port_wake_on_bits(struct xhci_hcd *xhci)
>> +{
>> +	int port_index;
>> +	__le32 __iomem **port_array;
>> +	unsigned long flags;
>> +	u32 t1, t2;
>> +
>> +	spin_lock_irqsave(&xhci->lock, flags);
>> +
>> +	/* disble usb3 ports Wake bits*/
>> +	port_index = xhci->num_usb3_ports;
>> +	port_array = xhci->usb3_ports;
>> +	while (port_index--) {
>> +		t1 = readl(port_array[port_index]);
>> +		t2 = xhci_port_state_to_neutral(t1);
>> +		t2 &= ~PORT_WAKE_BITS;
>> +		t1 = xhci_port_state_to_neutral(t1);
>> +		if (t1 != t2)
>> +			writel(t2, port_array[port_index]);
>> +	}
>> +
>> +	/* disble usb2 ports Wake bits*/
>> +	port_index = xhci->num_usb2_ports;
>> +	port_array = xhci->usb2_ports;
>> +	while (port_index--) {
>> +		t1 = readl(port_array[port_index]);
>> +		t2 = xhci_port_state_to_neutral(t1);
>> +		t2 &= ~PORT_WAKE_BITS;
>> +		t1 = xhci_port_state_to_neutral(t1);
>> +		if (t1 != t2)
>> +			writel(t2, port_array[port_index]);
>> +	}
>> +
>> +	spin_unlock_irqrestore(&xhci->lock, flags);
>> +}
>> +
>>   /*
>>    * Stop HC (not bus-specific)
>>    *
>> @@ -868,6 +906,10 @@ int xhci_suspend(struct xhci_hcd *xhci)
>>   			xhci->shared_hcd->state != HC_STATE_SUSPENDED)
>>   		return -EINVAL;
>>   
>> +	/* Clear root port wake on bits if not wakeup capable. */
>> +	if (!device_may_wakeup(hcd->self.controller))
>> +		xhci_disable_port_wake_on_bits(xhci);
>> +
>>   	/* Don't poll the roothubs on bus suspend. */
>>   	xhci_dbg(xhci, "%s: stopping port polling.\n", __func__);
>>   	clear_bit(HCD_FLAG_POLL_RH, &hcd->flags);
> This is better but still wrong.  Remember, this same code gets called
> for system suspend _and_ for runtime suspend.  During runtime suspend,
> wakeup is always supposed to be turned on, even if device_may_wakeup()
> is false.  That's because device_may_wakeup() refers only to system
> suspend.  What you need to test is the do_wakeup flag, which should be
> passed into xhci_suspend() by xhci_pci_suspend() and
> xhci_plat_suspend().
Yes, it should cover runtime suspend as well. Thanks for the comments. I 
will resend the patch.

> Another problem is in the patch description and the comments.  If
> device_may_wakeup() returns false, it doesn't mean the controller isn't
> wakeup-capable -- it means the controller isn't _allowed_ to wake up
> the system.  Those are two different things.

Accept, I will change this in new patch version.
>
> Finally, the code in xhci_disable_port_wake_on_bits() looks a little
> peculiar -- I'm not sure about all those calls to
> xhci_port_state_to_neutral().  But I'm not an expert on that; Mathias
> will have to advise on it.
This part of code was written with reference to code in xhci-hub.c.

Comments of xhci_port_state_to_neutral():
/*
  * Given a port state, this function returns a value that would result 
in the
  * port being in the same state, if the value was written to the port 
status
  * control register.
  * Save Read Only (RO) bits and save read/write bits where
  * writing a 0 clears the bit and writing a 1 sets the bit (RWS).
  * For all other types (RW1S, RW1CS, RW, and RZ), writing a '0' has no 
effect.
  */

This calculation is used to avoid side effect of changing other bit fields.

Thanks,
-baolu

>
> Alan Stern
>