Re: [PATCH v5 4/8] drm/cma-helper: Use the generic fbdev emulation

From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To: John Stultz <john.stultz@linaro.org>
Cc: "David Lechner" <david@lechnology.com>,
	"Xinliang Liu" <xinliang.liu@linaro.org>,
	"Intel Graphics Development" <intel-gfx@lists.freedesktop.org>,
	dri-devel <dri-devel@lists.freedesktop.org>,
	"Noralf Trønnes" <noralf@tronnes.org>
Subject: Re: [PATCH v5 4/8] drm/cma-helper: Use the generic fbdev emulation
Date: Thu, 23 Aug 2018 23:49:54 +0300	[thread overview]
Message-ID: <2601561.YhrFMFhLQ8@avalon> (raw)
In-Reply-To: <CALAqxLUyMi_J0XQCo_sqL6CTrxpvdkGqq6BWFBhL9=dtBb=nOw@mail.gmail.com>

Hi John,

On Thursday, 23 August 2018 20:48:40 EEST John Stultz wrote:
> On Thu, Aug 23, 2018 at 1:09 AM, Daniel Vetter <daniel@ffwll.ch> wrote:
> > On Thu, Aug 23, 2018 at 10:46:15AM +0300, Laurent Pinchart wrote:
> >> On Thursday, 23 August 2018 07:14:08 EEST John Stultz wrote:
> >>> On Mon, Aug 20, 2018 at 11:44 PM, John Stultz wrote:
> >>>> Hey Noralf, all,
> >>>> 
> >>>>   I've been digging for a bit on the regression that this patch has
> >>>> 
> >>>> tripped on the HiKey board as reported here:
> >>>> https://lkml.org/lkml/2018/8/16/81
> >>>> 
> >>>> The first issue was that the kirin driver was setting
> >>>> mode_config.max_width/height = 2048, which was causing errors as the
> >>>> the requested resolution was 1920x2160 (due to surfaceflinger
> >>>> requesting y*2 for page flipping).
> >>> 
> >>> Hey Noralf,
> >>> 
> >>>   Sorry, I know your probably sick of me. But I just wanted to circle
> >>> 
> >>> around on this little bit. So part of the issue I found earlier, was
> >>> that I'm running w/ CONFIG_DRM_FBDEV_OVERALLOC=200, to support
> >>> Surfaceflinger's request for page flipping.
> >> 
> >> Possibly slightly out of topic, but we're in 2018, is there any plan to
> >> make SurfaceFlinger move away from FBDEV ?
> > 
> > Is surfaceflinger really using direct fbdev still (maybe for boot-up)? Or
> > is this just an artifact of the mali blob hwcomposer backend?
> 
> Mostly its due to the simple fbdev being a legacy solution on android
> that works out of the box.
> I do suspect the android devs hope to retire it, which is why I'm
> working on getting things going w/ the drm_hwcomposer right now so we
> can get away from the fbdev.

That would be good news. Are there many Android components other than vendor-
specific hwcomposer implementations that still use fbdev ?

> But in the meantime, keeping the fbdev method running is important so we
> have a functioning device for testing AOSP w/ mainline.

-- 
Regards,

Laurent Pinchart

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