On 13/9/19 10:58 pm, Mathias Nyman wrote:
> On 12.9.2019 17.49, Jan Schmidt wrote:
>> If an endpoint is encountered that returns USB3_LPM_DEVICE_INITIATED,
>> keep
>> checking further endpoints, as there might be periodic endpoints later
>> that return USB3_LPM_DISABLED due to shorter service intervals.
>>
>> Without this, the code can set too high a maximum-exit-latency and
>> prevent the use of multiple USB3 cameras that should be able to work.
>>
>> Signed-off-by: Jan Schmidt <[email protected]>
>> Tested-by: Philipp Zabel <[email protected]>
>> ---
>> drivers/usb/host/xhci.c | 8 ++++----
>> 1 file changed, 4 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
>> index 03d1e552769b..1986b88661fc 100644
>> --- a/drivers/usb/host/xhci.c
>> +++ b/drivers/usb/host/xhci.c
>> @@ -4673,12 +4673,12 @@ static int
>> xhci_update_timeout_for_endpoint(struct xhci_hcd *xhci,
>> alt_timeout = xhci_call_host_update_timeout_for_endpoint(xhci,
>> udev,
>> desc, state, timeout);
>> - /* If we found we can't enable hub-initiated LPM, or
>> + /* If we found we can't enable hub-initiated LPM, and
>> * the U1 or U2 exit latency was too high to allow
>> - * device-initiated LPM as well, just stop searching.
>> + * device-initiated LPM as well, then we will disable LPM
>> + * for this device, so stop searching any further.
>> */
>> - if (alt_timeout == USB3_LPM_DISABLED ||
>> - alt_timeout == USB3_LPM_DEVICE_INITIATED) {
>> + if (alt_timeout == USB3_LPM_DISABLED) {
>> *timeout = alt_timeout;
>> return -E2BIG;
>> }
>>
>
> Thanks, nice catch. Adding to queue.
Great news for the Oculus Rift support we're working on :)
> While looking at this I see we have a similar issue if driver has
> "disable_hub_initiated_lpm" flag set.
>
> xhci_get_timeout_no_hub_lpm() might return USB3_LPM_DEVICE_INITIATED
> before we check if periodic endpoints would require disabling LPM
> completely.
Indeed - sorry, I didn't even think to look past the immediate issue.
> xhci_calculate_lpm_timeout()
> ...
> for (i = 0; i < config->desc.bNumInterfaces; i++) {
> ...
> if (intf->dev.driver) {
> ...
> if (driver && driver->disable_hub_initiated_lpm) {
> return xhci_get_timeout_no_hub_lpm(udev, state);
>
> I'll write a patch for that
I'll be happy to test by hard-coding the flag.
- Jan.
>
> -Mathias
--
Jan Schmidt, Centricular Ltd - https://centricular.com/
