On Fri, Oct 27, 2023 at 11:49:13AM -0400, Alan Stern wrote: > On Fri, Oct 27, 2023 at 05:20:29PM +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> > > --- > > Reviewed-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> @Greg KH, Friendly reminder. Thanks, Hardik
