Messages in this thread | | | Date | Fri, 31 Mar 2006 16:01:17 -0600 | Subject | Re: [PATCH 1/6] PCIERR : interfaces for synchronous I/O error detection on driver | From | (Linas Vepstas) |
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On Mon, Mar 27, 2006 at 11:37:36AM +0900, Hidetoshi Seto wrote: > - State check would be architecture dependent routine work.
I read through your patches. You are proposing a very different way of handling PCI errors than the pci_error_handlers API. It seems to be much more invasive, and I don't understand why its needed or how its better. Let me be specific:
In the mpt code you have a function called pciras_readl() that tries to perform an error-free read by retrying the read:
do { pcierr_clear(&cookie, ioc->pcidev); val = ioread32(addr); status = pcierr_read(&cookie); } while(status && (--retries > 0));
Why not create special arch/ia_64 readl routine to do this? In that case, other device drivers would get the benefit of the retry-on-error type read.
Now, you probably shouldn't put this into the default readl routine, since some devices do peculiar things if the same register is read repeatedly.
Next, I notice that if the repeated read fails, then
schedule_work(&mptbase_rstTask);
is called. This seems to be exactly the kind of action that the pci_error_handlers API was meant to provide: if there is a pci read error that cannot be trivially recovered, then the error_detected() &c. routines would be called. The mpt device driver would then initiate a mptbase_rstTask upon one of these callbacks.
Thus, in the ia64 code, if a repeated readl fails, then the ia64 reset task calls the device drivers error_detected() routine, followed by the drivers's link_reset() routine, followed by the resume() routine.
For the mpt, it would probably be resume() that was a wrapper around mptbase_rstTask(). Wouldn't this work just as well?
--linas
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