RE: [PATCH] video imx-ipu-fb: add clear screen

[Alex Gershgorin <alexg@meprolight.com>]

Hi Sascha,
 
On Mon, Sep 10, 2012 at 01:16:26PM +0300, Alex Gershgorin wrote:
> > Hi Sascha,
> >
> >  On Fri, Sep 07, 2012 at 01:46:39PM +0300, Alex Gershgorin wrote:
> > > This patch clear screen before usage
> > >
> > > Signed-off-by: Alex Gershgorin <alexg@meprolight.com>
> > > ---
> > >  drivers/video/imx-ipu-fb.c |    4 ++++
> > >  1 files changed, 4 insertions(+), 0 deletions(-)
> > >
> > > diff --git a/drivers/video/imx-ipu-fb.c b/drivers/video/imx-ipu-fb.c
> > > index 8039de0..d46cced 100644
> > > --- a/drivers/video/imx-ipu-fb.c
> > > +++ b/drivers/video/imx-ipu-fb.c
> > > @@ -1012,6 +1012,10 @@ static int imxfb_probe(struct device_d *dev)
> > >                                              (info->bits_per_pixel >> 3));
> > >               if (!fbi->info.screen_base)
> > >                       return -ENOMEM;
> > > +
> > > +             /* Clear the screen */
> > > +             memset((char *)fbi->info.screen_base, 0,
> > > +             info->xres * info->yres * (info->bits_per_pixel >> 3));
> >
> > > > Not clearing the screen is intentional. Normally the fb drivers do not
> > > > enable the framebuffer until explicitely requested via fb0.enable=1. The
> > > > environment normally is supposed to set a picture on the screen and
> > > > enable it afterwards.
> > > > That said, we can clear the screen as with MMU enabled this probably
> > > > does not take long time. But then it should be done in the fb core.
> >
> > Thanks for your explanation.
> > In my case, I displayed picture on the screen, of course as you said I added to "init" script
> > fb0.enable = 1
> > bmp / env / logo.bmp

>   I would exchange the above commands. I don't know how this looks on your
>   hardware, but often enough it looks a lot nicer if you draw the logo
>   first and enable the framebuffer (the backlight most importantly)
>   afterwards.

Oh sorry it's my fault, but in the my script this written correctly :-)  

> it was easy.
>
> The problem is that I have a screen with resolution 800x600, but
> picture that I displayed on the my screen is much smaller, resulting
> in a picture is displayed fine, but on the sides I get garbage.  This
> patch fixes this issue, of course it is not the only way to solve this
> issue.

> Yes, I thought that. 'cp /dev/zero /dev/fb0' would be another solution.
> I think the memset in the fb code is fine, but it should be done in the
> generic code.

Thanks for this point I tested it, this work fine :-) 

Regards,
Alex

 
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