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Date: Tue, 5 May 2015 02:14:04 +0200
From: "Luis R. Rodriguez" <mcgrof@...e.com>
To: Greg KH <gregkh@...uxfoundation.org>
Cc: "Luis R. Rodriguez" <mcgrof@...not-panic.com>,
sudipm.mukherjee@...il.com, teddy.wang@...iconmotion.com,
devel@...verdev.osuosl.org, luto@...capital.net,
cocci@...teme.lip6.fr, Suresh Siddha <sbsiddha@...il.com>,
Ingo Molnar <mingo@...e.hu>,
Thomas Gleixner <tglx@...utronix.de>,
Juergen Gross <jgross@...e.com>,
Daniel Vetter <daniel.vetter@...ll.ch>,
Dave Airlie <airlied@...hat.com>,
Antonino Daplas <adaplas@...il.com>,
Jean-Christophe Plagniol-Villard <plagnioj@...osoft.com>,
Tomi Valkeinen <tomi.valkeinen@...com>,
linux-fbdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3] staging: sm750fb: use arch_phys_wc_add() and
ioremap_wc()
On Sun, May 03, 2015 at 09:24:59PM +0200, Greg KH wrote:
> On Tue, Apr 21, 2015 at 01:12:03PM -0700, Luis R. Rodriguez wrote:
> > From: "Luis R. Rodriguez" <mcgrof@...e.com>
> >
> > The same area used for ioremap() is used for the MTRR area.
> > Convert the driver from using the x86 specific MTRR code to
> > the architecture agnostic arch_phys_wc_add(). arch_phys_wc_add()
> > will avoid MTRR if write-combining is available, in order to
> > take advantage of that also ensure the ioremap'd area is requested
> > as write-combining.
> >
> > There are a few motivations for this:
> >
> > a) Take advantage of PAT when available
> >
> > b) Help bury MTRR code away, MTRR is architecture specific and on
> > x86 its replaced by PAT
> >
> > c) Help with the goal of eventually using _PAGE_CACHE_UC over
> > _PAGE_CACHE_UC_MINUS on x86 on ioremap_nocache() (see commit
> > de33c442e titled "x86 PAT: fix performance drop for glx,
> > use UC minus for ioremap(), ioremap_nocache() and
> > pci_mmap_page_range()")
> >
> > The conversion done is expressed by the following Coccinelle
> > SmPL patch, it additionally required manual intervention to
> > address all the #ifdery and removal of redundant things which
> > arch_phys_wc_add() already addresses such as verbose message
> > about when MTRR fails and doing nothing when we didn't get
> > an MTRR.
> >
> > @ mtrr_found @
> > expression index, base, size;
> > @@
> >
> > -index = mtrr_add(base, size, MTRR_TYPE_WRCOMB, 1);
> > +index = arch_phys_wc_add(base, size);
> >
> > @ mtrr_rm depends on mtrr_found @
> > expression mtrr_found.index, mtrr_found.base, mtrr_found.size;
> > @@
> >
> > -mtrr_del(index, base, size);
> > +arch_phys_wc_del(index);
> >
> > @ mtrr_rm_zero_arg depends on mtrr_found @
> > expression mtrr_found.index;
> > @@
> >
> > -mtrr_del(index, 0, 0);
> > +arch_phys_wc_del(index);
> >
> > @ mtrr_rm_fb_info depends on mtrr_found @
> > struct fb_info *info;
> > expression mtrr_found.index;
> > @@
> >
> > -mtrr_del(index, info->fix.smem_start, info->fix.smem_len);
> > +arch_phys_wc_del(index);
> >
> > @ ioremap_replace_nocache depends on mtrr_found @
> > struct fb_info *info;
> > expression base, size;
> > @@
> >
> > -info->screen_base = ioremap_nocache(base, size);
> > +info->screen_base = ioremap_wc(base, size);
> >
> > @ ioremap_replace_default depends on mtrr_found @
> > struct fb_info *info;
> > expression base, size;
> > @@
> >
> > -info->screen_base = ioremap(base, size);
> > +info->screen_base = ioremap_wc(base, size);
> >
> > Generated-by: Coccinelle SmPL
> > Cc: Sudip Mukherjee <sudipm.mukherjee@...il.com>
> > Cc: Teddy Wang <teddy.wang@...iconmotion.com>
> > Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
> > Cc: Suresh Siddha <sbsiddha@...il.com>
> > Cc: Ingo Molnar <mingo@...e.hu>
> > Cc: Thomas Gleixner <tglx@...utronix.de>
> > Cc: Juergen Gross <jgross@...e.com>
> > Cc: Daniel Vetter <daniel.vetter@...ll.ch>
> > Cc: Andy Lutomirski <luto@...capital.net>
> > Cc: Dave Airlie <airlied@...hat.com>
> > Cc: Antonino Daplas <adaplas@...il.com>
> > Cc: Jean-Christophe Plagniol-Villard <plagnioj@...osoft.com>
> > Cc: Tomi Valkeinen <tomi.valkeinen@...com>
> > Cc: devel@...verdev.osuosl.org
> > Cc: linux-fbdev@...r.kernel.org
> > Cc: linux-kernel@...r.kernel.org
> > Signed-off-by: Luis R. Rodriguez <mcgrof@...e.com>
> > ---
> > drivers/staging/sm750fb/sm750.c | 36 ++++--------------------------------
> > drivers/staging/sm750fb/sm750.h | 3 ---
> > drivers/staging/sm750fb/sm750_hw.c | 3 +--
> > 3 files changed, 5 insertions(+), 37 deletions(-)
>
> This doesn't apply to my staging-next branch :(
OK I'll resend a v4 now.
Luis
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