Re: [Qemu-devel] [PATCH v2] console: Correct computation of bytes per pixel from bits per pixel

[Stefan Weil <sw@weilnetz.de>]

Am 22.08.2012 17:32, schrieb Jan Kiszka:
> On 2012-08-22 17:19, BALATON Zoltan wrote:
>> Division with round up is the correct way to compute this even if the
>> only case where division with round down gives incorrect result is
>> probably 15 bpp. This case was explicitely patched up in one of these
>> functions but was unhandled in the other. (I'm not sure about setting
>> 16 bpp for the 15bpp case either but I left that there for now.)
>>
>> Signed-off-by: BALATON Zoltan <balaton@eik.bme.hu>
>> ---
>>   console.c |    5 ++---
>>   1 file changed, 2 insertions(+), 3 deletions(-)
>>
>>   v2: Use DIV_ROUND_UP and extended commit message
>>
>> diff --git a/console.c b/console.c
>> index 4525cc7..9df1701 100644
>> --- a/console.c
>> +++ b/console.c
>> @@ -1612,7 +1612,7 @@ PixelFormat
>> qemu_different_endianness_pixelformat(int bpp)
>>       memset(&pf, 0x00, sizeof(PixelFormat));
>>
>>       pf.bits_per_pixel = bpp;
>> -    pf.bytes_per_pixel = bpp / 8;
>> +    pf.bytes_per_pixel = DIV_ROUND_UP(bpp, 8);
>>       pf.depth = bpp == 32 ? 24 : bpp;
>>
>>       switch (bpp) {
>> @@ -1661,13 +1661,12 @@ PixelFormat qemu_default_pixelformat(int bpp)
>>       memset(&pf, 0x00, sizeof(PixelFormat));
>>
>>       pf.bits_per_pixel = bpp;
>> -    pf.bytes_per_pixel = bpp / 8;
>> +    pf.bytes_per_pixel = DIV_ROUND_UP(bpp, 8);
>>       pf.depth = bpp == 32 ? 24 : bpp;
>>
>>       switch (bpp) {
>>           case 15:
>>               pf.bits_per_pixel = 16;
>> -            pf.bytes_per_pixel = 2;
> Removed unintentionally?
>
> Jan

15 bpp no longer needs special handling because
the computation above is fixed by the same patch,
so the removal is correct.

Stefan