Re: [PATCH v2 12/12] JUST FOR TEST: Add one-shot trigger to update display

[Mark Zhang <markz-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>]

Oh.. understood. Thanks.

Mark
On 07/03/2015 04:03 PM, Daniel Vetter wrote:
> On Fri, Jul 03, 2015 at 03:57:55PM +0800, Mark Zhang wrote:
>> On 07/01/2015 10:55 PM, Daniel Vetter wrote:
>>> On Wed, Jul 01, 2015 at 08:43:01PM +0800, Mark Zhang wrote:
>>>> On 07/01/2015 06:34 PM, Daniel Vetter wrote:
>> [...]
>>>>>
>>>>
>>>> Alright, this makes sense. I have no idea about qxl, what I have now is
>>>> an ubuntu running on Tegra114. So I'm wondering what I suppose to do is
>>>> installing qemu on the ubuntu?
>>>
>>> My suggestion is just to take the qxl code, move it to the fbdev emulation
>>> helper, make it generic and use it. If you want you can do a
>>> compile-tested patch on top to switch qxl over to the newly added helpers.
>>> No need to install/run qxl itself. Just that qxl seems to have the most
>>> complete solution for what you need.
>>
>> OK, thanks Daniel. I'm not quite familiar with the userspace, but I
>> think this is the summary:
>>
>> - For legacy FB support, we can use the "->dirty" fops, port the qxl
>> codes to drm_fb_helper.c, just as you described.
> 
> Note that this is for legacy frontbuffer rendering only. All other screen
> updates (setplane, setcrtc, pageflip) will go through the atomic flip
> path, thanks to all the atomic helpers.
> 
>> - For atomic page flip, the one-shot can be triggered when flipping the
>> window/plane.
>> - How about the front buffer rendering/drawing? I mean, if a drm
>> userspace app requests a dumb buffer then draws on it, how can we
>> trigger the one-shot to update the display? Do we need to add an
>> additional IOCTL to do that?
> 
> dumb buffer userspace is required to call dirtyfb ioctl.
> -Daniel
>