2012/6/11, Russell King - ARM Linux <linux@xxxxxxxxxxxxxxxx>:
> On Mon, Jun 11, 2012 at 09:06:48AM +0800, Liu Ying wrote:
>> This patch checks if framebuffer is unblanked before
>> we actually trigger panning in custom pan display
>> function.
>>
>> Signed-off-by: Liu Ying <Ying.Liu@xxxxxxxxxxxxx>
>> ---
>> drivers/video/mx3fb.c | 5 +++++
>> 1 files changed, 5 insertions(+), 0 deletions(-)
>>
>> diff --git a/drivers/video/mx3fb.c b/drivers/video/mx3fb.c
>> index e3406ab..d53db60 100644
>> --- a/drivers/video/mx3fb.c
>> +++ b/drivers/video/mx3fb.c
>> @@ -1063,6 +1063,11 @@ static int mx3fb_pan_display(struct
>> fb_var_screeninfo *var,
>> dev_dbg(fbi->device, "%s [%c]\n", __func__,
>> list_empty(&mx3_fbi->idmac_channel->queue) ? '-' : '+');
>>
>> + if (mx3_fbi->blank != FB_BLANK_UNBLANK) {
>> + dev_dbg(fbi->device, "panning with fb blanked not supported\n");
>> + return -EFAULT;
>> + }
>
> Why is this an error, and why return -EFAULT? What userspace access
> failed?
>
Hi, Russell,
IMHO, panning with framebuffer blanked is meaningless, at least, it is
not a common usecase. Most users use pan display to swap front buffer
and back buffer when framebuffer is unblanked/active. So, I choose to
take the in question case as an error. Pan display may let user select
a buffer address to be active on display and I saw the head file
'errno-base.h' comments EFAULT macro to be 'Bad address', so I use
this return value. Perhaps, this return value is not good enough.
Maybe, EIO is better? Would you please help to give some advice on
this?
Thanks.
--
Best Regards,
Liu Ying
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