lkml.org 
[lkml]   [2001]   [Jun]   [4]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: Missing cache flush.
Date

jgarzik@mandrakesoft.com said:
> > I was pointed at Documentation/DMA-mapping.txt but that doesn't seem
> > very helpful - it's very PCI-specific, and a quick perusal of
> > pci_dma_sync() on i386 shows that it doesn't do what's required anyway.

> What should it do on i386? mb()?

For it to have any use in the situation I described, it would need to
writeback and invalidate the dcache for the affected range. It doesn't seem
to do so, so it seems that it isn't what I require.

The situation is simple - I have a paged RAM setup and I need it cached.
All I want to do is flush and invalidate the cache when I'm about to waggle
whatever I/O ports I waggle to change pages.

There are other situations in which I need the cache flushed, but the above
is one of the simplest.

Even flush_page_to_ram() doesn't seem to do what its name implies, on most
architectures.

--
dwmw2


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 12:54    [W:0.359 / U:0.460 seconds]
©2003-2011 Jasper Spaans. Advertise on this site