[U-Boot] [PATCH RESEND] video:cache:fix: Buffer alignment and dcache flush for lcd subsystem

[Anatolij Gustschin]

Hi Simon, Lukasz,

On Sun, 6 Jan 2013 07:47:58 -0800
Simon Glass <sjg at chromium.org> wrote:
...
> >> > diff --git a/common/cmd_bmp.c b/common/cmd_bmp.c
> >> > index 5a52edd..57f3eb5 100644
> >> > --- a/common/cmd_bmp.c
> >> > +++ b/common/cmd_bmp.c
> >> > @@ -55,7 +55,7 @@ bmp_image_t *gunzip_bmp(unsigned long addr,
> >> > unsigned long *lenp)
> >> >          * Decompress bmp image
> >> >          */
> >> >         len = CONFIG_SYS_VIDEO_LOGO_MAX_SIZE;
> >> > -       dst = malloc(CONFIG_SYS_VIDEO_LOGO_MAX_SIZE);
> >> > +       dst = memalign(CONFIG_SYS_CACHELINE_SIZE, len);
> >>
> >> Why do you need to align this one? It is just returned to the caller,
> >> isn't it?
> >
> > Yes, it is returned to the caller, but afterwards lcd_display_bitmap
> > takes this pointer (and thereof probably unaligned buffer) and works on
> > it. (At least in the case of trats the bmp is gzipped).
> 
> OK, so it is directly used as a frame buffer? 

the allocated area isn't directly used as a frame buffer, it is
a buffer for bmp image which will be processed by lcd_display_bitmap().
The latter looks at the image header/palette and fills the
frame buffer (lcd_base) with the image data. This image buffer can
be unaligned I think.

Thanks,
Anatolij