Re: [PATCH] pci: introduce users of ioremap_pcibar()

[Alan Cox <alan@lxorguk.ukuu.org.uk>]

> FTR, I like this interface better since most drivers use ioremap() instead
> of ioremap_nocache(). They generally should be using the latter.

And pci_iomap is cleaner still. Plus pcim_iomap does resource tracking so
all the masses of special case error code/cleanup can get cut down.

> Is there any easy way to tell if the device driver should be using
> uncached mappings vs cacheable mappings?
> (Just from looking at the source code)

There isn't one.

> For storage/networking/audio cards I'm comfortable with the generalization
> that they all should use uncacheable mappings (I'm sure there are some
> exceptions.) I'm not with video devices.

There are exceptions - I2O for example and there are other cards that use
write merging when possible beyond video. Also btw vidoe depends on the
chip - if you cache/write merge the framebuffer on a Voodoo 1/2 card you
must be in 24/32bit video modes for example.

Generally though PCI = controlled by hardware = uncached

Alan