Messages in this thread | | | Date | Wed, 8 Mar 2023 22:49:47 +0100 | Subject | Re: [PATCH v4 1/4] video: fbdev: atyfb: only use ioremap_uc() on i386 and ia64 | From | Helge Deller <> |
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On 3/8/23 22:34, Arnd Bergmann wrote: > 0On Wed, Mar 8, 2023, at 21:01, Luis Chamberlain wrote: >> On Wed, Mar 08, 2023 at 09:07:07PM +0800, Baoquan He wrote: >>> From: Arnd Bergmann <arnd@arndb.de> >>> >>> ioremap_uc() is only meaningful on old x86-32 systems with the PAT >>> extension, and on ia64 with its slightly unconventional ioremap() >>> behavior, everywhere else this is the same as ioremap() anyway. >>> >>> Change the only driver that still references ioremap_uc() to only do so >>> on x86-32/ia64 in order to allow removing that interface at some >>> point in the future for the other architectures. >>> >>> On some architectures, ioremap_uc() just returns NULL, changing >>> the driver to call ioremap() means that they now have a chance >>> of working correctly. >>> >>> Signed-off-by: Arnd Bergmann <arnd@arndb.de> >>> Signed-off-by: Baoquan He <bhe@redhat.com> >>> Cc: Helge Deller <deller@gmx.de> >>> Cc: Thomas Zimmermann <tzimmermann@suse.de> >>> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> >>> Cc: linux-fbdev@vger.kernel.org >>> Cc: dri-devel@lists.freedesktop.org >> >> Reviewed-by: Luis Chamberlain <mcgrof@kernel.org> >> >> Is anyone using this driver these days? How often do fbdev drivers get >> audited to see what can be nuked? > > Geert already mentioned that this one is likely used on old > powermac systems.
and the latest generation of parisc machines use it too.
In addition, on parisc machines it's also important to map all io-space memory uncacheable. Since ioremap() takes care of it anyway, the ioremap_uc() was simply referencing the call to ioremap().
Helge
> I think my arm boardfile removal orphaned > some other fbdev drivers though. I removed the ones that can > no longer be enabled, but think a bunch of other ones > are still selectable but have no platform_device definition > or DT support: FB_PXA168, FB_DA8XX, FB_MX3, and MMP_FB. > > These four platforms are all still supported with DT, but > over time it gets less likely that anyone is still interested > in adding DT support to the fbdev drivers. > > Arnd
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