Messages in this thread | | | Date | Wed, 18 May 2016 14:54:25 -0400 (EDT) | From | Alan Stern <> | Subject | Re: [PATCH] usb: echi-hcd: Add register access check in shutdown |
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On Wed, 18 May 2016, Srinivas Kandagatla wrote:
> On 18/05/16 15:56, Alan Stern wrote: > > This doesn't seem like the right place. What you really should do is > > skip calling ehci_silence_controller() if the hardware isn't > > accessible. That's where the hardware gets touched, not in > > ehci_shutdown(). > > Just tried this suggestion, this would not work as well, Its not just > the hardware registers, which are of concern here, but also the rest of > the things like ehci->hrtimer pointer which are allocated or initialized > as part of ehci_setup(). > > Either the msm controller driver is not correct or we should have a way > to stop calling ehci_shutdown() if there was no ehci_setup() done yet. > > Any suggestions?
Yes, you're right.
Since you're concerned about more than just accessing the hardware registers, HW_ACCESSIBLE isn't the right thing to test. You need something that gets set in ehci_setup() and nowhere else.
One possibility is ehci->sbrn. If that is equal to 0 then ehci_setup() hasn't run, so ehci->shutdown() can simply return. Be sure to put a comment in the code explaining the reason for doing this.
Alan Stern
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