On Sun, Sep 23, 2001 at 11:31:51PM -0400, Dmitri Katchalov wrote:
> I'm writing a usermode driver for my Brother MFC 4600 printer/scanner/fax.
> The driver periodically polls the device for incoming data packets
> by switching to IEEE reverse byte mode, reading the data (if any) from
> the port and then switching back to compat mode.
> It works OK as long as the computer is idle. As soon as I put any kind of
> load on a CPU (even running ps on another console)
> ioctl (parport,PPNEGOT,&IEEE_MODE_BYTE) starts failing with
> "input/output error".
> I'm running 2.4.7 kernel on P120 Toshiba laptop.
> Parport driver correctly auto-detects TRISTATE, ECP, DMA and IRQ settings
> and otherwise appears to be configured and functioning properly.
> Any ideas?
I _guess_ that there is a schedule() in a timing-critical piece of
code. Is there anything in the output of 'dmesg' to suggest where
exactly the I/O error is originating, i.e. which event number?
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This archive was generated by hypermail 2b29 : Thu Oct 11 2001 - 06:43:57 EDT