From: Daniel Vetter <daniel@ffwll.ch>
To: Linus Walleij <linus.walleij@linaro.org>
Cc: Neil Armstrong <narmstrong@baylibre.com>,
Sean Paul <sean@poorly.run>,
Kevin Brodsky <Kevin.Brodsky@arm.com>,
Russell King <linux@armlinux.org.uk>,
ML dri-devel <dri-devel@lists.freedesktop.org>,
Eric Anholt <eric@anholt.net>, Daniel Vetter <daniel@ffwll.ch>,
Peter Collingbourne <pcc@google.com>,
Linux ARM <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH] Revert "video: fbdev: amba-clcd: Retire elder CLCD driver"
Date: Wed, 30 Sep 2020 11:40:39 +0200 [thread overview]
Message-ID: <20200930094039.GU438822@phenom.ffwll.local> (raw)
In-Reply-To: <CACRpkdYoOVeEkF6RiJSUykJfmJUthXNHMdTUmu+02OXRCgOd0A@mail.gmail.com>
On Tue, Sep 29, 2020 at 10:29:22PM +0200, Linus Walleij wrote:
> On Tue, Sep 29, 2020 at 8:44 PM Daniel Vetter <daniel@ffwll.ch> wrote:
> > On Tue, Sep 29, 2020 at 7:49 PM Peter Collingbourne <pcc@google.com> wrote:
>
> > But aside from all this, why is this blocking the migration from fbdev
> > to drm? With fbdev you don't have buffer allocations, nor dma-buf
> > support, and somehow android can boot.
>
> I do not know how Android does things these days but back in the
> days it would request a virtual framebuffer twice the height of the
> physical framebuffer and then pan that up/down between composing
> frames, thus achieving a type of double-buffering from userspace.
>
> Given the type of bugs Peter is seeing this seems to still be the
> case, Peter can you confirm?
We have the overallocate option for the fbdev emulation to support this
use case of flipping buffers. So this part should work I think, but maybe
some other parts of our check_var/set_par implementation don't work in a
way to make surface flinger happy.
-Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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next prev parent reply other threads:[~2020-09-30 9:42 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-28 20:08 [PATCH] Revert "video: fbdev: amba-clcd: Retire elder CLCD driver" Peter Collingbourne
2020-09-29 7:28 ` Neil Armstrong
2020-09-29 9:32 ` Daniel Vetter
2020-09-29 16:30 ` Peter Collingbourne
2020-09-29 16:48 ` Daniel Vetter
2020-09-29 16:52 ` Daniel Vetter
2020-09-29 17:49 ` Peter Collingbourne
2020-09-29 18:41 ` Daniel Vetter
2020-09-29 18:44 ` Daniel Vetter
2020-09-29 20:29 ` Linus Walleij
2020-09-29 21:37 ` Peter Collingbourne
2020-09-30 9:40 ` Daniel Vetter [this message]
2020-09-29 20:51 ` Peter Collingbourne
2020-09-30 9:43 ` Daniel Vetter
2020-10-12 12:50 ` Neil Armstrong
2021-12-05 13:34 ` Linus Walleij
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