Hi,
On Fri, Aug 18, 2017 at 3:22 PM, Felipe Balbi
<felipe.balbi@xxxxxxxxxxxxxxx> wrote:
>
> hi,
>
> Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx> writes:
>> When plugging Logitech C920 webcam, warning messages filled up dmesg:
>> [77117.655018] xhci_hcd 0000:0c:00.0: WARN Successful completion on short TX: needs XHCI_TRUST_TX_LENGTH quirk?
>> [77117.659018] xhci_hcd 0000:0c:00.0: WARN Successful completion on short TX: needs XHCI_TRUST_TX_LENGTH quirk?
>
> have you confirmed this is needed for this controller?
I just found commit d2f48f05cd2a2 ("usb: xhci: ASMedia ASM1042A
chipset need shorts TX quirk") and did the same thing for this
controller.
> Anybody from Renesas has confirmed it?
No, it's a user reported problem, please check the bug report in the link.
> Do you have an errata document to refer to?
No. Probably need Renesas guy to provide it.
>
>> [77122.622952] handle_tx_event: 541 callbacks suppressed
>>
>> No more warning messages with XHCI_TRUST_TX_LENGTH applied.
>>
>> BugLink: https://bugs.launchpad.net/bugs/1710548
>> Signed-off-by: Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx>
>> ---
>> drivers/usb/host/xhci-pci.c | 4 +++-
>> 1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
>> index 8071c8fdd15e..8566b43e19ba 100644
>> --- a/drivers/usb/host/xhci-pci.c
>> +++ b/drivers/usb/host/xhci-pci.c
>> @@ -202,8 +202,10 @@ static void xhci_pci_quirks(struct device *dev, struct xhci_hcd *xhci)
>> xhci->quirks |= XHCI_BROKEN_STREAMS;
>> }
>> if (pdev->vendor == PCI_VENDOR_ID_RENESAS &&
>> - pdev->device == 0x0015)
>> + pdev->device == 0x0015) {
>
> unnecessary
>
>> xhci->quirks |= XHCI_RESET_ON_RESUME;
>> + xhci->quirks |= XHCI_TRUST_TX_LENGTH;
>
> xhci->quirks |= XHCI_RESET_ON_RESUME |
> XHCI_TRUST_TX_LENGTH;
>
>> + }
>
> unnecessary
Do you mean that this quirk just hide the warning, it doesn't fix the
root cause?
>
> --
> balbi
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