Re: [parisc-linux] B2k and CONFIG_PDC_CONSOLE pb: followup

["Joel Soete" <soete.joel@tiscali.be>]

Hi Grant,

Just need more advise (sorry)

>It's the other way around. pdc_suspend_usb() is breaking PDC_CONSOLE.
>See email related to linux-2.6 c3000 serial console problems late last year.

Ok I find relevant info and pdf docs (in fact I missed 'data_formats.pdf'
to make the bridge :( )

>AFAIK, the memcpy just enables the PDC to use a serial console.

Hmm we didn't 'relocate' PDC (as see hpux makes), so all those information
are fill in by PDC prgm itself? So if Console is flagged CL_DUP, I don't
see why do we have to make this memcpy?

>But pdc_suspend_usb() apperently blows away the whole suckyio chip
>and thus PDC can no longer use suckyio serial either. Hrmm..I thought
>there was a IO_RESET_AND_CLEAR pdc call in that same chunk of code.

>Anyway, Figuring out some additional info could help:
>   (a) know which devices migh have DMA enabled when the OS gets control

May be the console itself (by continuously reading the kdb eg)?

>   (b) disable just the DMA
where should I look to disable so console dma?
[if I well understand spinlock_... and unlock function are not foreseen in
that case but more to avoid 2 different cpu to access a same ressource.
May be better something similar to [acquire,release]_console_sem?]

>   (c) detect when PDC_CONSOLE wants to use a device whose DMA we've disabled

Thanks in advance for additional help,
    Joel


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