Re: [Qemu-devel] [PATCH 3/8] hw/display/pxa2xx_lcd: Fix 16bpp+alpha and 18bpp+alpha palette formats

[Peter Maydell <peter.maydell@linaro.org>]

On 10 May 2014 00:35, Peter Crosthwaite <peter.crosthwaite@xilinx.com> wrote:
> On Fri, May 9, 2014 at 4:46 AM, Peter Maydell <peter.maydell@linaro.org> wrote:
>> The pxa2xx palette entry "16bpp plus transparency" format is
>> xxxxxxxTRRRRR000GGGGGG00BBBBB000, and "18bpp plus transparency" is
>> xxxxxxxTRRRRRR00GGGGGG00BBBBBB00.
>>
>> Correct errors in the code for reading these and converting
>> them to the internal format. In particular, the buggy code
>> was attempting to mask out bit 24 of a uint16_t, which
>> Coverity spotted as an error.
>>
>> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
>> ---
>>  hw/display/pxa2xx_lcd.c | 14 +++++++-------
>>  1 file changed, 7 insertions(+), 7 deletions(-)
>>
>> diff --git a/hw/display/pxa2xx_lcd.c b/hw/display/pxa2xx_lcd.c
>> index 09cdf17..fce013d 100644
>> --- a/hw/display/pxa2xx_lcd.c
>> +++ b/hw/display/pxa2xx_lcd.c
>> @@ -620,13 +620,13 @@ static void pxa2xx_palette_parse(PXA2xxLCDState *s, int ch, int bpp)
>>              src += 2;
>>              break;
>>          case 1: /* 16 bpp plus transparency */
>> -            alpha = *(uint16_t *) src & (1 << 24);
>> +            alpha = *(uint32_t *) src & (1 << 24);
>>              if (s->control[0] & LCCR0_CMS)
>> -                r = g = b = *(uint16_t *) src & 0xff;
>> +                r = g = b = *(uint32_t *) src & 0xff;
>>              else {
>> -                r = (*(uint16_t *) src & 0xf800) >> 8;
>> -                g = (*(uint16_t *) src & 0x07e0) >> 3;
>> -                b = (*(uint16_t *) src & 0x001f) << 3;
>> +                r = (*(uint32_t *) src & 0x7c0000) >> 15;
>
> 16BPP format (pasted from above with byte spacing)
> xxxxxxxT RRRRR000 GGGGGG00 BBBBB000
>
> So shouldn't r be 0xf80000 >> 16?

Yep, you're right. My first attempt at this I read the wrong
diagram from the manual (the framebuffer pixel formats are
different from the palette formats) and failed to spot I
hadn't corrected the code completely.

Since this is the only patch in this set that needs a
respin, and they're all independent fixes, I'll put the
other 7 into target-arm.next and just resend this.

thanks
-- PMM