Re: Linux 2.4.21-pre3-ac4

[Benjamin Herrenschmidt <benh _at_ xxxxxxxxxxxxxxxxxxx>]

On Sun, 2003-01-12 at 21:27, Alan Cox wrote:

> which currently has two problems Ross found
> 
> 1.  The processors or so fast we have to enforce the 400nS delay nowdays

What about PCI write posting ? How can we enforce the 400ns delay here ?
I suspect we can't read back from the taskfile registers after writing
the command. Especially when using DMA, I think I remember Andre telling
me even tapping alt status might not be safe... So we need to issue
a read from the same bus path, but not on any taskfile register from
this channel... hrm... any idea ?

> 2.  The code is racey in some situations with a shared IRQ because we
> may get an IRQ after we set the handler but before we send the command,
> or implemnted the other way the command can complete before we set the
> handler.

Yup, that's an old problem indeed.

Ben.

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