From: Maxime Ripard <maxime.ripard@free-electrons.com>
To: Chen-Yu Tsai <wens@csie.org>
Cc: David Airlie <airlied@linux.ie>,
dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org,
linux-sunxi@googlegroups.com
Subject: Re: [PATCH 5/7] drm/sun4i: backend: Offset layer buffer address by DRAM starting address
Date: Mon, 16 Oct 2017 10:00:43 +0200 [thread overview]
Message-ID: <20171016080043.xqpcxj7xfckcxdem@flea.lan> (raw)
In-Reply-To: <20171014040252.9621-6-wens@csie.org>
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Hi,
I've applied all the other patches.
On Sat, Oct 14, 2017 at 12:02:50PM +0800, Chen-Yu Tsai wrote:
> The display backend, as well as other peripherals that have a DRAM
> clock gate and access DRAM directly, bypassing the system bus,
> address the DRAM starting from 0x0, while physical addresses the
> system uses starts from 0x40000000 (or 0x20000000 in A80's case).
>
> Correct the address configured into the backend layer registers
> by PHYS_OFFSET to account for this.
However, I'm a bit confused at this.
The driver has been working so far, which it wouldn't have been able
to if the address was wrong. How was this problem noticed, and how can
that fix not be an issue in itself?
Thanks!
Maxime
--
Maxime Ripard, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com
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next prev parent reply other threads:[~2017-10-16 8:01 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-14 4:02 [PATCH 0/7] drm/sun4i: More cleanups Chen-Yu Tsai
2017-10-14 4:02 ` [PATCH 1/7] drm/sun4i: don't add components that are already in the queue Chen-Yu Tsai
2017-10-14 4:02 ` [PATCH 2/7] drm/sun4i: backend: Create regmap after access is possible Chen-Yu Tsai
2017-10-14 4:02 ` [PATCH 3/7] drm/sun4i: backend: Use drm_fb_cma_get_gem_addr() to get display memory Chen-Yu Tsai
2017-10-14 4:02 ` [PATCH 4/7] drm/sun4i: backend: Add comment explaining why registers are cleared Chen-Yu Tsai
2017-10-14 4:02 ` [PATCH 5/7] drm/sun4i: backend: Offset layer buffer address by DRAM starting address Chen-Yu Tsai
2017-10-16 8:00 ` Maxime Ripard [this message]
2017-10-16 8:20 ` [linux-sunxi] " Chen-Yu Tsai
2017-10-16 20:15 ` Maxime Ripard
2017-10-17 3:40 ` Chen-Yu Tsai
2017-10-16 9:42 ` icenowy
2017-10-14 4:02 ` [PATCH 6/7] drm/sun4i: hdmi: Document PAD_CTRL1 output invert bits Chen-Yu Tsai
2017-10-14 4:02 ` [PATCH 7/7] drm/sun4i: hdmi: Move PAD_CTRL1 setting to mode_set function Chen-Yu Tsai
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