On Thu, Oct 26, 2023 at 02:34:22PM -0400, Alan Stern wrote: > On Thu, Oct 26, 2023 at 12:15:51PM +0200, Hardik Gajjar wrote: > > This patch introduces a new USB quirk, > > USB_QUIRK_SHORT_SET_ADDRESS_REQ_TIMEOUT, which modifies the timeout value > > for the 'SET_ADDRESS' request. The standard timeout for USB request/command > > is 5000 ms, as recommended in the USB 3.2 specification (section 9.2.6.1). > > > > However, certain scenarios, such as connecting devices through an APTIV > > hub, can lead to timeout errors when the device enumerates as full speed > > initially and later switches to high speed during chirp negotiation. > > > > In such cases, USB analyzer logs reveal that the bus suspends for > > 5 seconds due to incorrect chirp parsing and resumes only after two > > consecutive timeout errors trigger a hub driver reset. > > > > Packet(54) Dir(?) Full Speed J(997.100 us) Idle( 2.850 us) > > _______| Time Stamp(28 . 105 910 682) > > _______|_____________________________________________________________Ch0 > > Packet(55) Dir(?) Full Speed J(997.118 us) Idle( 2.850 us) > > _______| Time Stamp(28 . 106 910 632) > > _______|_____________________________________________________________Ch0 > > Packet(56) Dir(?) Full Speed J(399.650 us) Idle(222.582 us) > > _______| Time Stamp(28 . 107 910 600) > > _______|_____________________________________________________________Ch0 > > Packet(57) Dir Chirp J( 23.955 ms) Idle(115.169 ms) > > _______| Time Stamp(28 . 108 532 832) > > _______|_____________________________________________________________Ch0 > > Packet(58) Dir(?) Full Speed J (Suspend)( 5.347 sec) Idle( 5.366 us) > > _______| Time Stamp(28 . 247 657 600) > > _______|_____________________________________________________________Ch0 > > > > This 5-second delay in device enumeration is undesirable, particularly > > in automotive applications where quick enumeration is crucial > > (ideally within 3 seconds). > > > > The newly introduced quirks provide the flexibility to align with a > > 3-second time limit, as required in specific contexts like automotive > > applications. > > > > By reducing the 'SET_ADDRESS' request timeout to 500 ms, the > > system can respond more swiftly to errors, initiate rapid recovery, and > > ensure efficient device enumeration. This change is vital for scenarios > > where rapid smartphone enumeration and screen projection are essential. > > > > To use the quirk, please write "vendor_id:product_id:p" to > > /sys/bus/usb/drivers/hub/module/parameter/quirks > > > > For example, > > echo "0x2c48:0x0132:p" > /sys/bus/usb/drivers/hub/module/parameters/quirks" > > > > Signed-off-by: Hardik Gajjar <hgajjar@xxxxxxxxxxxxxx> > > --- > > For the usbcore parts: A couple of very minor things can be improved. > Once those improvements have been made, you can add: > > Reviewed-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> > > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > > index 0a1731a0f0ef..4aa3723d2eaf 100644 > > --- a/Documentation/admin-guide/kernel-parameters.txt > > +++ b/Documentation/admin-guide/kernel-parameters.txt > > @@ -6817,6 +6817,9 @@ > > pause after every control message); > > o = USB_QUIRK_HUB_SLOW_RESET (Hub needs extra > > delay after resetting its port); > > + p = USB_QUIRK_SHORT_SET_ADDRESS_REQ_TIMEOUT (Reduce > > + timeout of the SET_ADDRESS request from > > + 5000 ms to 500 ms) > > To avoid going over the 80-column limit, move "(Reduce" to the next > line and reflow the text in parentheses. > > > diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c > > index 3c54b218301c..98db92af2cce 100644 > > --- a/drivers/usb/core/hub.c > > +++ b/drivers/usb/core/hub.c > > @@ -54,6 +54,19 @@ > > #define USB_TP_TRANSMISSION_DELAY_MAX 65535 /* ns */ > > #define USB_PING_RESPONSE_TIME 400 /* ns */ > > > > +/* > > + * USB 3.2 spec, section 9.2.6.1 > > + * USB sets an upper limit of 5000 ms for any command/request > > + * to be processed. > > + */ > > +#define USB_DEFAULT_REQUEST_TIMEOUT_MS 5000 /* ms */ > > You don't need to define this macro at all. Just use > USB_CTRL_SET_TIMEOUT (which is already defined to be 5000) as the > existing code already does. > > > +/* > > + * The SET_ADDRESS request timeout will be 500 ms when > > + * USB_QUIRK_SHORT_SET_ADDRESS_REQ_TIMEOUT enable. > > + */ > > +#define USB_SHORT_SET_ADDRESS_REQ_TIMEOUT_MS 500 /* ms */ > > As remarked earlier, we don't need to have the "_MS" suffix on either > the macro name or the "timeout_ms" variable name. Removing the suffix > will be more consistent with the USB_TP_TRANSMISSION_DELAY_MAX and > USB_PING_RESPONSE_TIME names you see above. I understand the suffix _MS in macro but the suffix is variable name was added after the comment about timeout unit from Greg in patchV2. https://marc.info/?l=linux-usb&m=169687322126192&w=2 Other comments will be resolved in next patch. > > > + > > +/* > > + * The SET_ADDRESS request timeout will be 500 ms when > > + * USB_QUIRK_SHORT_SET_ADDRESS_REQ_TIMEOUT enable. > > Change the second line to: > > * the USB_QUIRK_SHORT_SET_ADDRESS_REQ_TIMEOUT quirk flag is set. > > > + */ > > +#define USB_SHORT_SET_ADDRESS_REQ_TIMEOUT_MS 500 /* ms */ > > Overall, I agree with Sergey that this would be cleaner if you split it > up into two patches. The first should change the comment for the > set_address() callback function and the implementation in xhci-hcd. The > second should add the quirk flag and make the corresponding changes to > the USB core. > > Alan Stern Thanks, Hardik
