Messages in this thread | | | Date | Tue, 22 Nov 2022 09:44:22 +0000 | From | Jonathan Cameron <> | Subject | Re: [PATCH 1/2] cxl/mbox: Add background operation handling machinery |
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On Mon, 21 Nov 2022 13:48:04 -0800 Davidlohr Bueso <dave@stgolabs.net> wrote:
> On Thu, 25 Aug 2022, Jonathan Cameron wrote: > > >> +/* > >> + * Ensure that ->mbox_send() can run safely when a background > >> + * command is running. If so, returns zero, otherwise -EBUSY. > > > >As above, I'm not sure this is necessary given you should get > >a sensible error code in response to any such message. > >E.g. media disabled. > > So this is necessary to prevent mischief in the polling case > where you can have windows where the driver is out of sync > with the hardware - hw finishes async command but driver > (sleeping poller) has not acknowledged this. In the irq case, > yeah this would be redundant and not needed. >
Ok. A worked example might be useful for where this matters at a higher level. For example, if there is no conflict at the hardware level what goes wrong in the software as a result of dropping the protection on the one that we haven't yet detected as finished...
Jonathan
> Thanks, > Davidlohr
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