Hi,
I found on my machine(lenovo T410), most of time only reading the status
register in the entry of ehci_irq may take 2~4 microseconds, and sometimes
it is extremely slow and the read can consume > 100 microseconds.
I measure the time by adding two trace events around the below line in
entry of ehci_irq().
status = ehci_readl(ehci, &ehci->regs->status)
Looks it should be a platform-dependent issue and I didn't
observe that on some arm platform.
Could anyone give a hint about the problem?
Thanks,
--
Ming Lei
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