Xhci controllers with hci_version > 0.96 gives spurious success
events on short packet completion. During webcam capture the
"ERROR Transfer event TRB DMA ptr not part of current TD" was observed.
The same application works fine with synopsis controllers hci_version 0.96.
The same Issue is seen with Intel Pantherpoint xhci controller. So enabling
this quirk in xhci_gen_setup if controller verion is greater than 0.96.
For xhci-pci move the quirk to much generic place xhci_gen_setup.
Signed-off-by: George Cherian <[email protected]>
---
drivers/usb/host/xhci-pci.c | 1 -
drivers/usb/host/xhci.c | 7 +++++++
2 files changed, 7 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
index cc24e39..f00cb20 100644
--- a/drivers/usb/host/xhci-pci.c
+++ b/drivers/usb/host/xhci-pci.c
@@ -93,7 +93,6 @@ static void xhci_pci_quirks(struct device *dev, struct xhci_hcd *xhci)
}
if (pdev->vendor == PCI_VENDOR_ID_INTEL &&
pdev->device == PCI_DEVICE_ID_INTEL_PANTHERPOINT_XHCI) {
- xhci->quirks |= XHCI_SPURIOUS_SUCCESS;
xhci->quirks |= XHCI_EP_LIMIT_QUIRK;
xhci->limit_active_eps = 64;
xhci->quirks |= XHCI_SW_BW_CHECKING;
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index d8f640b..0f7be59 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -4697,6 +4697,13 @@ int xhci_gen_setup(struct usb_hcd *hcd, xhci_get_quirks_t get_quirks)
get_quirks(dev, xhci);
+ /* In xhci controllers which follow xhci 1.0 spec gives a spurious
+ * success event after a short transfer. This quirk will ignore such
+ * spurious event.
+ */
+ if (xhci->hci_version > 0x96)
+ xhci->quirks |= XHCI_SPURIOUS_SUCCESS;
+
/* Make sure the HC is halted. */
retval = xhci_halt(xhci);
if (retval)
--
1.8.1.4
Thanks George, this looks fine. I will munge the description a bit when
I commit it, and mark it for stable as well.
Unfortunately, due to the timing of the merge window, this patch will
have to wait for 2-3 weeks until 3.11-rc1 is out.
Sarah Sharp
On Mon, Jul 01, 2013 at 10:59:12AM +0530, George Cherian wrote:
> Xhci controllers with hci_version > 0.96 gives spurious success
> events on short packet completion. During webcam capture the
> "ERROR Transfer event TRB DMA ptr not part of current TD" was observed.
> The same application works fine with synopsis controllers hci_version 0.96.
> The same Issue is seen with Intel Pantherpoint xhci controller. So enabling
> this quirk in xhci_gen_setup if controller verion is greater than 0.96.
> For xhci-pci move the quirk to much generic place xhci_gen_setup.
>
> Signed-off-by: George Cherian <[email protected]>
> ---
> drivers/usb/host/xhci-pci.c | 1 -
> drivers/usb/host/xhci.c | 7 +++++++
> 2 files changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
> index cc24e39..f00cb20 100644
> --- a/drivers/usb/host/xhci-pci.c
> +++ b/drivers/usb/host/xhci-pci.c
> @@ -93,7 +93,6 @@ static void xhci_pci_quirks(struct device *dev, struct xhci_hcd *xhci)
> }
> if (pdev->vendor == PCI_VENDOR_ID_INTEL &&
> pdev->device == PCI_DEVICE_ID_INTEL_PANTHERPOINT_XHCI) {
> - xhci->quirks |= XHCI_SPURIOUS_SUCCESS;
> xhci->quirks |= XHCI_EP_LIMIT_QUIRK;
> xhci->limit_active_eps = 64;
> xhci->quirks |= XHCI_SW_BW_CHECKING;
> diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
> index d8f640b..0f7be59 100644
> --- a/drivers/usb/host/xhci.c
> +++ b/drivers/usb/host/xhci.c
> @@ -4697,6 +4697,13 @@ int xhci_gen_setup(struct usb_hcd *hcd, xhci_get_quirks_t get_quirks)
>
> get_quirks(dev, xhci);
>
> + /* In xhci controllers which follow xhci 1.0 spec gives a spurious
> + * success event after a short transfer. This quirk will ignore such
> + * spurious event.
> + */
> + if (xhci->hci_version > 0x96)
> + xhci->quirks |= XHCI_SPURIOUS_SUCCESS;
> +
> /* Make sure the HC is halted. */
> retval = xhci_halt(xhci);
> if (retval)
> --
> 1.8.1.4
>
Hi Sarah and George,
I met this issue at my side too. Per lspci output and HCIVERSION, I
see the host is Lynx
Point xhci 1.0 host.
I notice George's patch has not been merged in kernel 3.11-rc1.
Then I manually applied George's patch against 3.10.0 but the issue
still happen when I use
camera to capture picture. So I doubt some corner test has not been
covered by patch.
Pls let me know what I can do if you need more information.
Thanks,
Shuduo
On Tue, Jul 2, 2013 at 11:27 AM, Sarah Sharp
<[email protected]> wrote:
> Thanks George, this looks fine. I will munge the description a bit when
> I commit it, and mark it for stable as well.
>
> Unfortunately, due to the timing of the merge window, this patch will
> have to wait for 2-3 weeks until 3.11-rc1 is out.
>
> Sarah Sharp
>
> On Mon, Jul 01, 2013 at 10:59:12AM +0530, George Cherian wrote:
>> Xhci controllers with hci_version > 0.96 gives spurious success
>> events on short packet completion. During webcam capture the
>> "ERROR Transfer event TRB DMA ptr not part of current TD" was observed.
>> The same application works fine with synopsis controllers hci_version 0.96.
>> The same Issue is seen with Intel Pantherpoint xhci controller. So enabling
>> this quirk in xhci_gen_setup if controller verion is greater than 0.96.
>> For xhci-pci move the quirk to much generic place xhci_gen_setup.
>>
>> Signed-off-by: George Cherian <[email protected]>
>> ---
>> drivers/usb/host/xhci-pci.c | 1 -
>> drivers/usb/host/xhci.c | 7 +++++++
>> 2 files changed, 7 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
>> index cc24e39..f00cb20 100644
>> --- a/drivers/usb/host/xhci-pci.c
>> +++ b/drivers/usb/host/xhci-pci.c
>> @@ -93,7 +93,6 @@ static void xhci_pci_quirks(struct device *dev, struct xhci_hcd *xhci)
>> }
>> if (pdev->vendor == PCI_VENDOR_ID_INTEL &&
>> pdev->device == PCI_DEVICE_ID_INTEL_PANTHERPOINT_XHCI) {
>> - xhci->quirks |= XHCI_SPURIOUS_SUCCESS;
>> xhci->quirks |= XHCI_EP_LIMIT_QUIRK;
>> xhci->limit_active_eps = 64;
>> xhci->quirks |= XHCI_SW_BW_CHECKING;
>> diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
>> index d8f640b..0f7be59 100644
>> --- a/drivers/usb/host/xhci.c
>> +++ b/drivers/usb/host/xhci.c
>> @@ -4697,6 +4697,13 @@ int xhci_gen_setup(struct usb_hcd *hcd, xhci_get_quirks_t get_quirks)
>>
>> get_quirks(dev, xhci);
>>
>> + /* In xhci controllers which follow xhci 1.0 spec gives a spurious
>> + * success event after a short transfer. This quirk will ignore such
>> + * spurious event.
>> + */
>> + if (xhci->hci_version > 0x96)
>> + xhci->quirks |= XHCI_SPURIOUS_SUCCESS;
>> +
>> /* Make sure the HC is halted. */
>> retval = xhci_halt(xhci);
>> if (retval)
>> --
>> 1.8.1.4
>>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to [email protected]
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
Hi Shuduo,
On 7/22/2013 12:35 PM, Shuduo Sang wrote:
> Hi Sarah and George,
>
> I met this issue at my side too. Per lspci output and HCIVERSION, I
> see the host is Lynx
> Point xhci 1.0 host.
>
> I notice George's patch has not been merged in kernel 3.11-rc1.
Just to make sure, without the patch are you getting the following error.
"ERROR Transfer event TRB DMA ptr not part of current TD"
> Then I manually applied George's patch against 3.10.0 but the issue
> still happen when I use
> camera to capture picture.
Can you explain what is the exact issue you face after applying the patch?
Are you still getting
"ERROR Transfer event TRB DMA ptr not part of current TD"
> So I doubt some corner test has not been
> covered by patch.
> Pls let me know what I can do if you need more information.
>
> Thanks,
> Shuduo
>
> On Tue, Jul 2, 2013 at 11:27 AM, Sarah Sharp
> <[email protected]> wrote:
>> Thanks George, this looks fine. I will munge the description a bit when
>> I commit it, and mark it for stable as well.
>>
>> Unfortunately, due to the timing of the merge window, this patch will
>> have to wait for 2-3 weeks until 3.11-rc1 is out.
>>
>> Sarah Sharp
>>
>> On Mon, Jul 01, 2013 at 10:59:12AM +0530, George Cherian wrote:
>>> Xhci controllers with hci_version > 0.96 gives spurious success
>>> events on short packet completion. During webcam capture the
>>> "ERROR Transfer event TRB DMA ptr not part of current TD" was observed.
>>> The same application works fine with synopsis controllers hci_version 0.96.
>>> The same Issue is seen with Intel Pantherpoint xhci controller. So enabling
>>> this quirk in xhci_gen_setup if controller verion is greater than 0.96.
>>> For xhci-pci move the quirk to much generic place xhci_gen_setup.
>>>
>>> Signed-off-by: George Cherian <[email protected]>
>>> ---
>>> drivers/usb/host/xhci-pci.c | 1 -
>>> drivers/usb/host/xhci.c | 7 +++++++
>>> 2 files changed, 7 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
>>> index cc24e39..f00cb20 100644
>>> --- a/drivers/usb/host/xhci-pci.c
>>> +++ b/drivers/usb/host/xhci-pci.c
>>> @@ -93,7 +93,6 @@ static void xhci_pci_quirks(struct device *dev, struct xhci_hcd *xhci)
>>> }
>>> if (pdev->vendor == PCI_VENDOR_ID_INTEL &&
>>> pdev->device == PCI_DEVICE_ID_INTEL_PANTHERPOINT_XHCI) {
>>> - xhci->quirks |= XHCI_SPURIOUS_SUCCESS;
>>> xhci->quirks |= XHCI_EP_LIMIT_QUIRK;
>>> xhci->limit_active_eps = 64;
>>> xhci->quirks |= XHCI_SW_BW_CHECKING;
>>> diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
>>> index d8f640b..0f7be59 100644
>>> --- a/drivers/usb/host/xhci.c
>>> +++ b/drivers/usb/host/xhci.c
>>> @@ -4697,6 +4697,13 @@ int xhci_gen_setup(struct usb_hcd *hcd, xhci_get_quirks_t get_quirks)
>>>
>>> get_quirks(dev, xhci);
>>>
>>> + /* In xhci controllers which follow xhci 1.0 spec gives a spurious
>>> + * success event after a short transfer. This quirk will ignore such
>>> + * spurious event.
>>> + */
>>> + if (xhci->hci_version > 0x96)
>>> + xhci->quirks |= XHCI_SPURIOUS_SUCCESS;
>>> +
>>> /* Make sure the HC is halted. */
>>> retval = xhci_halt(xhci);
>>> if (retval)
>>> --
>>> 1.8.1.4
>>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
>> the body of a message to [email protected]
>> More majordomo info at http://vger.kernel.org/majordomo-info.html
>> Please read the FAQ at http://www.tux.org/lkml/
--
-George
On Mon, Jul 22, 2013 at 3:23 PM, George Cherian <[email protected]> wrote:
>
> Hi Shuduo,
>
>
> On 7/22/2013 12:35 PM, Shuduo Sang wrote:
>>
>> Hi Sarah and George,
>>
>> I met this issue at my side too. Per lspci output and HCIVERSION, I
>> see the host is Lynx
>> Point xhci 1.0 host.
>>
>> I notice George's patch has not been merged in kernel 3.11-rc1.
>
>
> Just to make sure, without the patch are you getting the following error.
>
>
> "ERROR Transfer event TRB DMA ptr not part of current TD"
>
Yes, I run below script to capture picture.
#!/bin/bash
# camera_stress.sh
# Testing the camera by BinLi
for ((i=0; i<10 ; i++))
do
fswebcam --no-banner -r 352x288 -d /dev/video0 test_$i.jpg
done
It will randomly fail at later loops. The fail rate about 20%~30%. When it fail,
I can see error messages by dmesg as below:
[ 68.171039] xhci_hcd 0000:00:14.0: ERROR Transfer event TRB DMA ptr
not part of current TD
[ 68.175030] xhci_hcd 0000:00:14.0: ERROR Transfer event TRB DMA ptr
not part of current TD
[ 68.179026] xhci_hcd 0000:00:14.0: ERROR Transfer event TRB DMA ptr
not part of current TD
[ 68.180082] usb 3-12: USB disconnect, device number 4
[ 68.450459] usb 3-12: new high-speed USB device number 5 using xhci_hcd
[ 68.477960] usb 3-12: New USB device found, idVendor=5986, idProduct=0397
[ 68.477964] usb 3-12: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[ 68.477966] usb 3-12: Product: Integrated Camera
[ 68.477968] usb 3-12: Manufacturer: Vimicro corp.
[ 68.479107] uvcvideo: Found UVC 1.00 device Integrated Camera (5986:0397)
[ 68.479821] input: Integrated Camera as
/devices/pci0000:00/0000:00:14.0/usb3/3-12/3-12:1.0/input/input15
[ 321.389721] type=1400 audit(1374214638.182:29): apparmor="DENIED"
operation="capable" parent=1 profile="/usr/sbin/cupsd" pid=1232
comm="cupsd" pid=1232 comm="cupsd" c
apability=36 capname="block_suspend"
>
>> Then I manually applied George's patch against 3.10.0 but the issue
>> still happen when I use
>> camera to capture picture.
>
>
> Can you explain what is the exact issue you face after applying the patch?
> Are you still getting
>
>
> "ERROR Transfer event TRB DMA ptr not part of current TD"
>
Yes, after I applied your patch manually, I still getting this error.
Seems fail rate is same.
>> So I doubt some corner test has not been
>> covered by patch.
>> Pls let me know what I can do if you need more information.
>>
>> Thanks,
>> Shuduo
>>
>> On Tue, Jul 2, 2013 at 11:27 AM, Sarah Sharp
>> <[email protected]> wrote:
>>>
>>> Thanks George, this looks fine. I will munge the description a bit when
>>> I commit it, and mark it for stable as well.
>>>
>>> Unfortunately, due to the timing of the merge window, this patch will
>>> have to wait for 2-3 weeks until 3.11-rc1 is out.
>>>
>>> Sarah Sharp
>>>
>>> On Mon, Jul 01, 2013 at 10:59:12AM +0530, George Cherian wrote:
>>>>
>>>> Xhci controllers with hci_version > 0.96 gives spurious success
>>>> events on short packet completion. During webcam capture the
>>>> "ERROR Transfer event TRB DMA ptr not part of current TD" was observed.
>>>> The same application works fine with synopsis controllers hci_version
>>>> 0.96.
>>>> The same Issue is seen with Intel Pantherpoint xhci controller. So
>>>> enabling
>>>> this quirk in xhci_gen_setup if controller verion is greater than 0.96.
>>>> For xhci-pci move the quirk to much generic place xhci_gen_setup.
>>>>
>>>> Signed-off-by: George Cherian <[email protected]>
>>>> ---
>>>> drivers/usb/host/xhci-pci.c | 1 -
>>>> drivers/usb/host/xhci.c | 7 +++++++
>>>> 2 files changed, 7 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
>>>> index cc24e39..f00cb20 100644
>>>> --- a/drivers/usb/host/xhci-pci.c
>>>> +++ b/drivers/usb/host/xhci-pci.c
>>>> @@ -93,7 +93,6 @@ static void xhci_pci_quirks(struct device *dev, struct
>>>> xhci_hcd *xhci)
>>>> }
>>>> if (pdev->vendor == PCI_VENDOR_ID_INTEL &&
>>>> pdev->device ==
>>>> PCI_DEVICE_ID_INTEL_PANTHERPOINT_XHCI) {
>>>> - xhci->quirks |= XHCI_SPURIOUS_SUCCESS;
>>>> xhci->quirks |= XHCI_EP_LIMIT_QUIRK;
>>>> xhci->limit_active_eps = 64;
>>>> xhci->quirks |= XHCI_SW_BW_CHECKING;
>>>> diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
>>>> index d8f640b..0f7be59 100644
>>>> --- a/drivers/usb/host/xhci.c
>>>> +++ b/drivers/usb/host/xhci.c
>>>> @@ -4697,6 +4697,13 @@ int xhci_gen_setup(struct usb_hcd *hcd,
>>>> xhci_get_quirks_t get_quirks)
>>>>
>>>> get_quirks(dev, xhci);
>>>>
>>>> + /* In xhci controllers which follow xhci 1.0 spec gives a spurious
>>>> + * success event after a short transfer. This quirk will ignore
>>>> such
>>>> + * spurious event.
>>>> + */
>>>> + if (xhci->hci_version > 0x96)
>>>> + xhci->quirks |= XHCI_SPURIOUS_SUCCESS;
>>>> +
>>>> /* Make sure the HC is halted. */
>>>> retval = xhci_halt(xhci);
>>>> if (retval)
>>>> --
>>>> 1.8.1.4
>>>>
>>> --
>>> To unsubscribe from this list: send the line "unsubscribe linux-kernel"
>>> in
>>> the body of a message to [email protected]
>>> More majordomo info at http://vger.kernel.org/majordomo-info.html
>>> Please read the FAQ at http://www.tux.org/lkml/
>
>
> --
> -George
>
On Mon, Jul 22, 2013 at 03:58:19PM +0800, Shuduo Sang wrote:
> On Mon, Jul 22, 2013 at 3:23 PM, George Cherian <[email protected]> wrote:
> Yes, I run below script to capture picture.
>
> #!/bin/bash
> # camera_stress.sh
> # Testing the camera by BinLi
>
> for ((i=0; i<10 ; i++))
> do
> fswebcam --no-banner -r 352x288 -d /dev/video0 test_$i.jpg
> done
>
> It will randomly fail at later loops. The fail rate about 20%~30%. When it fail,
> I can see error messages by dmesg as below:
>
> [ 68.171039] xhci_hcd 0000:00:14.0: ERROR Transfer event TRB DMA ptr
> not part of current TD
> [ 68.175030] xhci_hcd 0000:00:14.0: ERROR Transfer event TRB DMA ptr
> not part of current TD
> [ 68.179026] xhci_hcd 0000:00:14.0: ERROR Transfer event TRB DMA ptr
> not part of current TD
> [ 68.180082] usb 3-12: USB disconnect, device number 4
> [ 68.450459] usb 3-12: new high-speed USB device number 5 using xhci_hcd
> [ 68.477960] usb 3-12: New USB device found, idVendor=5986, idProduct=0397
> [ 68.477964] usb 3-12: New USB device strings: Mfr=1, Product=2, SerialNumber=0
> [ 68.477966] usb 3-12: Product: Integrated Camera
> [ 68.477968] usb 3-12: Manufacturer: Vimicro corp.
> [ 68.479107] uvcvideo: Found UVC 1.00 device Integrated Camera (5986:0397)
> [ 68.479821] input: Integrated Camera as
> /devices/pci0000:00/0000:00:14.0/usb3/3-12/3-12:1.0/input/input15
> [ 321.389721] type=1400 audit(1374214638.182:29): apparmor="DENIED"
> operation="capable" parent=1 profile="/usr/sbin/cupsd" pid=1232
> comm="cupsd" pid=1232 comm="cupsd" c
> apability=36 capname="block_suspend"
That's a different issue. The log shows that your USB webcam
disconnects, and that's why your script fails. Then the device
re-connects.
Do other USB devices work after the camera disconnects? Does the webcam
itself work (at least for a while) after you stop and restart the
script? (Note that after a disconnect, the webcam may be present on
/dev/video1 instead of /dev/video0, because your script had /dev/video0
open when the webcam re-connected.)
> >> Then I manually applied George's patch against 3.10.0 but the issue
> >> still happen when I use
> >> camera to capture picture.
> >
> > Can you explain what is the exact issue you face after applying the patch?
> > Are you still getting
> >
> > "ERROR Transfer event TRB DMA ptr not part of current TD"
>
> Yes, after I applied your patch manually, I still getting this error.
> Seems fail rate is same.
I'm still going to apply George's patch, because it does fix a different
issue.
I'm not sure if there's anything software can do if the webcam keeps
disconnecting. That's usually an electrical issue. Have you tried a
different USB cable? If the webcam is behind a hub, have you tried
connecting it directly to the computer's roothub? If it's attached to
the roothub, have you tried putting it behind an external hub?
If none of that works, I can look at your logs, and try to figure out if
there's anything software can do. Can you recompile your kernel with
George's patch and CONFIG_USB_DEBUG and CONFIG_USB_XHCI_HCD_DEBUGGING
turned on? Please send me the log from just before you start your
script to when the device disconnects.
Sarah Sharp
On Thu, Jul 25, 2013 at 12:30 AM, Sarah Sharp
<[email protected]> wrote:
> On Mon, Jul 22, 2013 at 03:58:19PM +0800, Shuduo Sang wrote:
>> On Mon, Jul 22, 2013 at 3:23 PM, George Cherian <[email protected]> wrote:
>> Yes, I run below script to capture picture.
>>
>> #!/bin/bash
>> # camera_stress.sh
>> # Testing the camera by BinLi
>>
>> for ((i=0; i<10 ; i++))
>> do
>> fswebcam --no-banner -r 352x288 -d /dev/video0 test_$i.jpg
>> done
>>
>> It will randomly fail at later loops. The fail rate about 20%~30%. When it fail,
>> I can see error messages by dmesg as below:
>>
>> [ 68.171039] xhci_hcd 0000:00:14.0: ERROR Transfer event TRB DMA ptr
>> not part of current TD
>> [ 68.175030] xhci_hcd 0000:00:14.0: ERROR Transfer event TRB DMA ptr
>> not part of current TD
>> [ 68.179026] xhci_hcd 0000:00:14.0: ERROR Transfer event TRB DMA ptr
>> not part of current TD
>> [ 68.180082] usb 3-12: USB disconnect, device number 4
>> [ 68.450459] usb 3-12: new high-speed USB device number 5 using xhci_hcd
>> [ 68.477960] usb 3-12: New USB device found, idVendor=5986, idProduct=0397
>> [ 68.477964] usb 3-12: New USB device strings: Mfr=1, Product=2, SerialNumber=0
>> [ 68.477966] usb 3-12: Product: Integrated Camera
>> [ 68.477968] usb 3-12: Manufacturer: Vimicro corp.
>> [ 68.479107] uvcvideo: Found UVC 1.00 device Integrated Camera (5986:0397)
>> [ 68.479821] input: Integrated Camera as
>> /devices/pci0000:00/0000:00:14.0/usb3/3-12/3-12:1.0/input/input15
>> [ 321.389721] type=1400 audit(1374214638.182:29): apparmor="DENIED"
>> operation="capable" parent=1 profile="/usr/sbin/cupsd" pid=1232
>> comm="cupsd" pid=1232 comm="cupsd" c
>> apability=36 capname="block_suspend"
>
> That's a different issue. The log shows that your USB webcam
> disconnects, and that's why your script fails. Then the device
> re-connects.
>
Hmm, I think you are right. I tried my script on another laptop with
Lynx Point host and same webcam, it works very well. Sorry if my
information misled you and George.
> Do other USB devices work after the camera disconnects? Does the webcam
> itself work (at least for a while) after you stop and restart the
> script? (Note that after a disconnect, the webcam may be present on
> /dev/video1 instead of /dev/video0, because your script had /dev/video0
> open when the webcam re-connected.)
>
>> >> Then I manually applied George's patch against 3.10.0 but the issue
>> >> still happen when I use
>> >> camera to capture picture.
>> >
>> > Can you explain what is the exact issue you face after applying the patch?
>> > Are you still getting
>> >
>> > "ERROR Transfer event TRB DMA ptr not part of current TD"
>>
>> Yes, after I applied your patch manually, I still getting this error.
>> Seems fail rate is same.
>
> I'm still going to apply George's patch, because it does fix a different
> issue.
>
Is there any code piece to triage the issue George's patch fix? Then I can
do some verification with George's patch or without.
> I'm not sure if there's anything software can do if the webcam keeps
> disconnecting. That's usually an electrical issue. Have you tried a
> different USB cable? If the webcam is behind a hub, have you tried
> connecting it directly to the computer's roothub? If it's attached to
> the roothub, have you tried putting it behind an external hub?
>
> If none of that works, I can look at your logs, and try to figure out if
> there's anything software can do. Can you recompile your kernel with
> George's patch and CONFIG_USB_DEBUG and CONFIG_USB_XHCI_HCD_DEBUGGING
> turned on? Please send me the log from just before you start your
> script to when the device disconnects.
>
> Sarah Sharp