* David Brownell | 2008-04-15 11:09:43 [-0700]:

>On Tuesday 15 April 2008, Sebastian Siewior wrote:
>> * David Brownell | 2008-04-14 16:23:36 [-0700]:
>> 
>> >On Monday 14 April 2008, Sebastian Siewior wrote:
>> >> Without this it is possible to unload the SPI-driver while an
>> >> spidev user open()ed the spidev device.
>> >
>> >Does that misbehave in any way?  That sort of unloading of
>>
>> Yes. Unload, read() -> Ooops.
>
>What's the oops, and with which controller driver?
I can't dump the Ooops right now. The conter driver is my own which is
based on mpc52xx_psc_spi.c.

>If the adapter is unloaded it's *supposed* to first complete
>all pending transfers (and prevent submission of new ones).
Yes, but the problem here is (I thing) that spidev doesn't know that the
driver is gone. spi_async() (what is called straight from spidev_read()
with no checks in between) is always using spi->master->* even if the
master is gone.

>And removing the subsidiary devices is supposed to unbind
>them ... though looking at it quickly, I suspect that the
>"spidev" driver doesn't check for unbound devices in its
>various I/O paths.
Aha. So you mean that the read function which was spidev_read() while
the controller was available should point to something else once the
controller is gone?

>
>So this sounds like a bug in the controller driver, or else
>in how spidev handles unbind.
I try to look later at spidev once I find something that does a similar
job and works as expected....

>- Dave
Sebastian

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