On 10/22/18 9:12 PM, Mathias Nyman wrote:
> On 21.10.2018 20:08, Aaron Ma wrote:
>> Realtek USB3.0 Card Reader [0bda:0328] reports wrong port status on
>> Cannon lake PCH USB3.1 xHCI [8086:a36d] after resume from S3,
>> after clear port reset it works fine.
>>
>> Since this device is registered on USB3 roothub at boot,
>> when port status reports not superspeed, xhci_get_port_status will call
>> an uninitialized completion in bus_state[0].
>> Kernel will hang because of NULL pointer.
>>
>> Restrict the USB2 resume status check in USB2 roothub to fix hang issue.
>> No harm to initialize USB3 bus_state[0] in case it is called.
>>
>> Signed-off-by: Aaron Ma <aaron.ma@xxxxxxxxxxxxx>
>> ---
>> drivers/usb/host/xhci-hub.c | 2 +-
>> drivers/usb/host/xhci-mem.c | 1 +
>> drivers/usb/host/xhci-ring.c | 2 +-
>> 3 files changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/usb/host/xhci-hub.c b/drivers/usb/host/xhci-hub.c
>> index 7e2a531ba321..d30ca6ceffc9 100644
>> --- a/drivers/usb/host/xhci-hub.c
>> +++ b/drivers/usb/host/xhci-hub.c
>> @@ -876,7 +876,7 @@ static u32 xhci_get_port_status(struct usb_hcd *hcd,
>> status |= USB_PORT_STAT_SUSPEND;
>> }
>> if ((raw_port_status & PORT_PLS_MASK) == XDEV_RESUME &&
>> - !DEV_SUPERSPEED_ANY(raw_port_status)) {
>> + !DEV_SUPERSPEED_ANY(raw_port_status) && 1 == hcd_index(hcd)) {
>> if ((raw_port_status & PORT_RESET) ||
>> !(raw_port_status & PORT_PE))
>> return 0xffffffff;
>
> Nice catch.
>
> Maybe use "hcd->speed < HCD_USB3" instead of "1 == hcd_index(hcd)"
> It's easier to understand.
>
> Turns out this isn't an issue with your Realtek device, it just happens
> to trigger
> a driver issue.
>
> The original !DEV_SUPERSPEED_ANY() check was not suitable here.
> It checks the port-speed field of portsc register (bits 13:10), which
> are only valid for USB3
> ports if all link training is done and port reached its "enabled" state.
> Otherwise it will return 0, and USB3 ports may be mistaken for USB2 ports.
PORT_ENABLE should be already set to one.
The same device ID card reader doesn't have issue on Sunrise Point.
Maybe it is related to Cannon lake PCH USB controller?
>
> Just to make sure, Does your device stay as a USB 3 device, it's never
> enumerated as USB2, right?
>
Right, always USB3.
> I'm in the middle of refactoring the get_port_status(), it should solve
> this
> as well, but we need your solution stable releases.
>
V2 sent out. Cc-ed stable.
> Any chance you to check if the refactored code works with the Realtek
> device?
> I just created a "get_port_status_refactor" branch for it:
>
> git://git.kernel.org/pub/scm/linux/kernel/git/mnyman/xhci.git
> get_port_status_refactor
The hang issue is not reproduced on this kernel branch.
Thanks,
Aaron
>
>> diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
>> index b1f27aa38b10..dd2ad50c5289 100644
>> --- a/drivers/usb/host/xhci-mem.c
>> +++ b/drivers/usb/host/xhci-mem.c
>> @@ -2539,6 +2539,7 @@ int xhci_mem_init(struct xhci_hcd *xhci, gfp_t
>> flags)
>> xhci->bus_state[0].resume_done[i] = 0;
>> xhci->bus_state[1].resume_done[i] = 0;
>> /* Only the USB 2.0 completions will ever be used. */
>> + init_completion(&xhci->bus_state[0].rexit_done[i]);
>> init_completion(&xhci->bus_state[1].rexit_done[i]);
>> }
>
> I don't think we should init the completion unnecessary for USB3 ports.
>
>> diff --git a/drivers/usb/host/xhci-ring.c
>> b/drivers/usb/host/xhci-ring.c
>> index f0a99aa0ac58..894d4625b8b9 100644
>> --- a/drivers/usb/host/xhci-ring.c
>> +++ b/drivers/usb/host/xhci-ring.c
>> @@ -1634,7 +1634,7 @@ static void handle_port_status(struct xhci_hcd
>> *xhci,
>> * RExit to a disconnect state). If so, let the the driver know
>> it's
>> * out of the RExit state.
>> */
>> - if (!DEV_SUPERSPEED_ANY(portsc) &&
>> + if (!DEV_SUPERSPEED_ANY(portsc) && 1 == hcd_index(hcd) &&
>> test_and_clear_bit(hcd_portnum,
>> &bus_state->rexit_ports)) {
>> complete(&bus_state->rexit_done[hcd_portnum]);
>>
>
> Same here, prefer hcd->speed < HCD_USB3
>
> Thanks
> Mathias
