I/O issues with writing to mtdblock devices on kirkwood

Mark Brown broonie at kernel.org
Tue Jan 12 10:02:23 PST 2016


On Tue, Jan 12, 2016 at 05:29:40PM +0100, Arnd Bergmann wrote:
> On Tuesday 12 January 2016 02:19:04 Andrew Lunn wrote:

> > When i played with this, i added a reschedule point at the end of the
> > drivers transfer_one_message() function, to see if that would help. It
> > did not, which is why i made a guess it has something to do with a
> > lock.

> Can you try using usleep_range() instead of udelay()? It might also

Oh, indeed - should've thought of that!

> be worth trying what the actual delay is for each byte to see if a
> longer sleep time would help, but I guess that time is highly
> device specific.

I expect that the delay will depend on the clock speed of the SPI bus
which is system dependant.  Might actually be worth checking if the bus
is clocked excessively slowly.
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