Hi Experts,
Now I meet a bad usb disk which may cause bios post hang. After tracing, I
find it is dead loop in a while() condition.
This usb disk's decriptor is as below, we could find that it reports it
has 3 endpoints, but it only report one of them. And when usb core function
sets config, in function XhcInitializeEndpointContext(), usb core function
will try to find all the endpoints, but it cannot meet the wanted type data to
exit, so it dead loop there. I see in UDK revision 14863, file UsbDesc.c has
been patched(MdeModulePkg/UsbBus: Stop parsing descriptor if some of descriptor
fields are invalid).
So we should do more patch under this condition?
Waiting your suggestion.
Thank you.
09 02 22 00 01 01 00 80 32 // CFG IFs=1
09 04 00 00 03 FF 01 01 00 // IF No=0 AS=0 EPs=3
09 21 10 01 21 01 22 43 00 // HID
07 05 81 03 08 00 02 // EP
while (EpDesc->DescriptorType != USB_DESC_TYPE_ENDPOINT) { //
XhcInitializeEndpointContext(), line 2607
EpDesc = (USB_ENDPOINT_DESCRIPTOR *)((UINTN)EpDesc + EpDesc->Length);
}
------------------
BR
winddy_zhang
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