[U-Boot] [PATCH 1/2] video:cache:fix: Proper buffer alignment for lcd subsystem

[Simon Glass]

Hi Lukasz,

On Tue, Jan 8, 2013 at 12:28 AM, Lukasz Majewski <l.majewski at samsung.com> wrote:
> Hi Simon,
>
>> Hi Lukasz,
>>
>> On Mon, Jan 7, 2013 at 1:23 AM, Lukasz Majewski
>> <l.majewski at samsung.com> wrote:
>> > This commit makes the video subsystem code cache aware.
>> > Memory allocated for decompressed BMP memory is now cache line
>> > aligned.
>> >
>> > Tested-by: Lukasz Majewski <l.majewski at samsung.com>
>> > Signed-off-by: Lukasz Majewski <l.majewski at samsung.com>
>> > Signed-off-by: Kyungmin Park <kyungmin.park at samsung.com>
>> > Cc: Anatolij Gustschin <agust at denx.de>
>> > ---
>> >  common/cmd_bmp.c |    2 +-
>> >  1 files changed, 1 insertions(+), 1 deletions(-)
>> >
>> > 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);
>> >         if (dst == NULL) {
>> >                 puts("Error: malloc in gunzip failed!\n");
>> >                 return NULL;
>>
>> Sorry, I still have a question. Does this 'dst' address get used as
>> the actual LCD frame buffer on your board, or is it just copied to the
>> frame buffer?
>>
>
> I must admit, that I've misunderstood the LCD code a bit. Reply to this
> post from Anatolij helped me.
> The buffer (dst) is only the "internal" buffer from which we are
> assigning BMP data to actual frame buffer area. Then only the frame
> buffer (pointed by fb pointer) area needs cache flush (which is done at
> lcd_sync()).

OK that makes sense, thanks.

>
> To sum up - this patch shall be dropped.
> However the second patch -
>
> [PATCH 2/2] video:cache:fix:trats: Enable dcache flush for TRATS
> board's LCD subsystem
>
> is crucial to fix the BMP image display distortion.

Yes I agree.

Regards,
Simon

> --
> Best regards,
>
> Lukasz Majewski
>
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