Re: [PATCH v3 05/12] s3c-fb: Add support for display panning

[Maurus Cuelenaere <mcuelenaere@gmail.com>]

 Op 02-07-10 13:25, Ben Dooks schreef:
> On 28/06/10 12:28, Maurus Cuelenaere wrote:
>>  Op 28-06-10 10:08, Pawel Osciak schreef:
>>> Supports all bpp modes.
>>>
>>> The PRTCON register is used to disable in-hardware updates of registers
>>> that store start and end addresses of framebuffer memory. This prevents
>>> display corruption in case we do not make it before VSYNC with updating
>>> them atomically. With this feature there is no need to wait for a VSYNC
>>> interrupt before each such update.
>>>
>>> Signed-off-by: Pawel Osciak <p.osciak@samsung.com>
>>> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
>>> ---
>>>  arch/arm/plat-samsung/include/plat/regs-fb.h |    5 ++
>>>  drivers/video/s3c-fb.c                       |   71 ++++++++++++++++++++++++++
>>>  2 files changed, 76 insertions(+), 0 deletions(-)
>>>
>>> diff --git a/arch/arm/plat-samsung/include/plat/regs-fb.h b/arch/arm/plat-samsung/include/plat/regs-fb.h
>>> index ac10013..f454e32 100644
>>> --- a/arch/arm/plat-samsung/include/plat/regs-fb.h
>>> +++ b/arch/arm/plat-samsung/include/plat/regs-fb.h
>>> @@ -112,6 +112,11 @@
>>>  #define VIDCON2_ORGYCbCr			(1 << 8)
>>>  #define VIDCON2_YUVORDCrCb			(1 << 7)
>>>  
>>> +/* PRTCON (S3C6410, S5PC100) */
>>> +
>>> +#define PRTCON					(0x0c)
>>> +#define PRTCON_PROTECT				(1 << 11)
>>> +
>>>  /* VIDTCON0 */
>>>  
>>>  #define VIDTCON0_VBPDE_MASK			(0xff << 24)
>>> diff --git a/drivers/video/s3c-fb.c b/drivers/video/s3c-fb.c
>>> index 59ac76a..4f3680d 100644
>>> --- a/drivers/video/s3c-fb.c
>>> +++ b/drivers/video/s3c-fb.c
>>> @@ -71,6 +71,7 @@ struct s3c_fb;
>>>   * @buf_end: Offset of buffer end registers.
>>>   * @osd: The base for the OSD registers.
>>>   * @palette: Address of palette memory, or 0 if none.
>>> + * @has_prtcon: Set if has PRTCON register.
>>>   */
>>>  struct s3c_fb_variant {
>>>  	unsigned int	is_2443:1;
>>> @@ -85,6 +86,8 @@ struct s3c_fb_variant {
>>>  	unsigned short	osd;
>>>  	unsigned short	osd_stride;
>>>  	unsigned short	palette[S3C_FB_MAX_WIN];
>>> +
>>> +	unsigned int	has_prtcon:1;
>>>  };
>>>  
>>>  /**
>>> @@ -379,6 +382,9 @@ static int s3c_fb_set_par(struct fb_info *info)
>>>  
>>>  	info->fix.line_length = (var->xres_virtual * var->bits_per_pixel) / 8;
>>>  
>>> +	info->fix.xpanstep = info->var.xres_virtual > info->var.xres ? 1 : 0;
>>> +	info->fix.ypanstep = info->var.yres_virtual > info->var.yres ? 1 : 0;
>> No need for the '? 1 : 0'
> I tihnk there is, IIRC there is no neccessity for a compiler to produce
> one for true, just that the result be !0

Hmm ok, I only checked this using GCC 4.4.3 and this:

#include <stdio.h>
#include <stdbool.h>

int main(void) {
    printf("%d %d\n", (int)(1 > 2), (int)(1 < 2));   // gives 0 1
    printf("%d %d\n", (bool)(1 > 2), (bool)(1 < 2)); // gives 0 1

    return 0;
}

-- 
Maurus Cuelenaere