On Wed, Sep 22, 2004 at 08:59:06AM -0700, Dave wrote:

quoted

It actually does work already on IA64.
Why would a writeb not work?  All it does is set the appropriate byte
selects.  The platform doesn't care what the register size is, and the
target (PCI chip) seems to be able to figure it out, so there must be
something else wrong.

What is an XScale, btw?

XScale is a CPU branched off from the ARM family by Intel. Mostly you
will see them in PDAs. However, there are other XScale platforms that
are used as network processors or I/O processors.  I probably need to
do some PCI-X sniffing but all I know currently is that after the
writeb the mask register remains unchanged. However if I do a writel
it changes. So currently if I load the driver as it is, I get
infinitely interrupt calls because the irq isn't masked and the irq
handler doesn't know what to do with the interrupt. Since this isn't
really a fast path routine anyhow, wouldn't it be better to make all
platforms happy?

The problem you have is that if you use writel, I think you'll be
subject to race conditions, unless you single thread updates of
the mask register among the different ports.  I don't know that they
are today (Jeff would), because different ports usually have separate
registers.

jeremy