Messages in this thread Patch in this message | | | From | Stefan Bauer <> | Subject | Re: [PATCH] i810fb: Fix console switch regression | Date | Mon, 17 Mar 2008 09:20:32 +0100 |
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Am Sonntag, 16. März 2008 20:48 schrieb Geert Uytterhoeven: > On Sun, 16 Mar 2008, Stefan Bauer wrote: > > --- linux-2.6/drivers/video/i810/i810_main.c.orig > > +++ linux-2.6/drivers/video/i810/i810_main.c > > @@ -1476,7 +1476,7 @@ static int i810fb_cursor(struct fb_info > > struct i810fb_par *par = info->par; > > u8 __iomem *mmio = par->mmio_start_virtual; > > > > - if (!(par->dev_flags & LOCKUP)) > > + if (!par->dev_flags & LOCKUP) > > return -ENXIO; > > However, the original expression didn't make sense, as LOCKUP is 8 and > !par->dev_flags is either 0 or 1, so `!par->dev_flags & LOCKUP' is > always 0. > > I took a quick look at the usage of the LOCKUP flag. Apparently when a > lock-up is detected, this flag is set, and the driver will fall back to > software operations instead of hardware accelerated operations. > > Is it possible the intended code was > > if (par->dev_flags & LOCKUP) > return -ENXIO; > > ?
Yes, IMO you are right. 4c7ffe0 ("fbdev: prevent drivers that have hardware cursors from calling software cursor code") introduced the senseless code.
I'm going on testing today, but I think that's it.
Again, please CC me, thanks.
--- From: Stefan Bauer <stefan.bauer@cs.tu-chemnitz.de>
Since 4c7ffe0b9f7f40bd818fe3af51342f64c483908e ("fbdev: prevent drivers that have hardware cursors from calling software cursor code") every call of i810fb_cursor fails with -ENXIO because of a incorrect "!".
This hasn't striked until eaa0ff15c30dc9799eb4d12660edb73aeb6d32c5 ("fix ! versus & precedence in various places") surrounded the expression with braces, so that the intended behavior was inverted. That caused 'pixel waste' - the same line of multi-colored pixels repeated over the whole screen - during console switch.
This switches back to the original pre-4c7ffe0 behavior.
Signed-off-by: Stefan Bauer <stefan.bauer@cs.tu-chemnitz.de> Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Antonino Daplas <adaplas@pol.net>
--- --- linux-2.6/drivers/video/i810/i810_main.c.orig +++ linux-2.6/drivers/video/i810/i810_main.c @@ -1476,7 +1476,7 @@ static int i810fb_cursor(struct fb_info struct i810fb_par *par = info->par; u8 __iomem *mmio = par->mmio_start_virtual;
- if (!(par->dev_flags & LOCKUP)) + if (par->dev_flags & LOCKUP) return -ENXIO;
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