Messages in this thread | | | From | David Woodhouse <> | Subject | Re: Missing cache flush. | Date | Tue, 05 Jun 2001 00:29:22 +0100 |
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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
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