From: "Roman Beranek" <romanberanek@icloud.com>
To: "Maxime Ripard" <maxime@cerno.tech>
Cc: "Frank Oltmanns" <frank@oltmanns.dev>,
"Chen-Yu Tsai" <wens@csie.org>,
"David Airlie" <airlied@gmail.com>,
"Daniel Vetter" <daniel@ffwll.ch>,
"Jernej Skrabec" <jernej.skrabec@gmail.com>,
"Samuel Holland" <samuel@sholland.org>,
<dri-devel@lists.freedesktop.org>,
<linux-arm-kernel@lists.infradead.org>,
<linux-sunxi@lists.linux.dev>, <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] drm/sun4i: uncouple DSI dotclock divider from TCON0_DCLK_REG
Date: Wed, 05 Apr 2023 14:34:11 +0200 [thread overview]
Message-ID: <CROTQHUM88W0.2URPO95U5ZMS5@void.crly.cz> (raw)
In-Reply-To: <20230329195802.veybo3367zifw77n@penduick>
Hello Maxime,
On Wed Mar 29, 2023 at 9:58 PM CEST, Maxime Ripard wrote:
> > In order to preserve semantic correctness however, I propose to preface
> > the change with a patch that renames sun4i_dotclock and tcon-pixel-clock
> > such that dot/pixel is replaced with d/data. What do you think?
>
> I don't think it's exposed to the userspace in any way so it makes sense to me
>
Here's a new series that includes those renames:
<https://lore.kernel.org/all/20230331110245.43527-1-me@crly.cz/>
It turns out however that the new dclk rates can't be set exactly as
requested without touching pll-video0*, tcon0 now therefore gets
reparented from pll-mipi to pll-video0-2x which, as it further turns
out, breaks DSI. While simply forbidding the video0-2x mux option seems
to me as the right way to go because there's not much use for it with
non-DSI interfaces either besides the opportunity to power pll-mipi
down, I'd like to run by you first.
Kind regards,
Roman
* As pll-mipi doesn't have CLK_SET_RATE_PARENT flag set, pll-video0
retains its boot-time rate of 294 MHz set by sunxi-dw-hdmi driver
in u-boot. Why 294 MHz (as opposed to the default rate of 297 MHz)?
The driver actually asks for 297 MHz, clock_set_pll3 rounds it to
294 MHz though because it limits itself to 6 MHz steps.
WARNING: multiple messages have this Message-ID (diff)
From: "Roman Beranek" <romanberanek@icloud.com>
To: "Maxime Ripard" <maxime@cerno.tech>
Cc: Samuel Holland <samuel@sholland.org>,
Frank Oltmanns <frank@oltmanns.dev>,
Jernej Skrabec <jernej.skrabec@gmail.com>,
linux-kernel@vger.kernel.org, Chen-Yu Tsai <wens@csie.org>,
dri-devel@lists.freedesktop.org, linux-sunxi@lists.linux.dev,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] drm/sun4i: uncouple DSI dotclock divider from TCON0_DCLK_REG
Date: Wed, 05 Apr 2023 14:34:11 +0200 [thread overview]
Message-ID: <CROTQHUM88W0.2URPO95U5ZMS5@void.crly.cz> (raw)
In-Reply-To: <20230329195802.veybo3367zifw77n@penduick>
Hello Maxime,
On Wed Mar 29, 2023 at 9:58 PM CEST, Maxime Ripard wrote:
> > In order to preserve semantic correctness however, I propose to preface
> > the change with a patch that renames sun4i_dotclock and tcon-pixel-clock
> > such that dot/pixel is replaced with d/data. What do you think?
>
> I don't think it's exposed to the userspace in any way so it makes sense to me
>
Here's a new series that includes those renames:
<https://lore.kernel.org/all/20230331110245.43527-1-me@crly.cz/>
It turns out however that the new dclk rates can't be set exactly as
requested without touching pll-video0*, tcon0 now therefore gets
reparented from pll-mipi to pll-video0-2x which, as it further turns
out, breaks DSI. While simply forbidding the video0-2x mux option seems
to me as the right way to go because there's not much use for it with
non-DSI interfaces either besides the opportunity to power pll-mipi
down, I'd like to run by you first.
Kind regards,
Roman
* As pll-mipi doesn't have CLK_SET_RATE_PARENT flag set, pll-video0
retains its boot-time rate of 294 MHz set by sunxi-dw-hdmi driver
in u-boot. Why 294 MHz (as opposed to the default rate of 297 MHz)?
The driver actually asks for 297 MHz, clock_set_pll3 rounds it to
294 MHz though because it limits itself to 6 MHz steps.
WARNING: multiple messages have this Message-ID (diff)
From: "Roman Beranek" <romanberanek@icloud.com>
To: "Maxime Ripard" <maxime@cerno.tech>
Cc: "Frank Oltmanns" <frank@oltmanns.dev>,
"Chen-Yu Tsai" <wens@csie.org>,
"David Airlie" <airlied@gmail.com>,
"Daniel Vetter" <daniel@ffwll.ch>,
"Jernej Skrabec" <jernej.skrabec@gmail.com>,
"Samuel Holland" <samuel@sholland.org>,
<dri-devel@lists.freedesktop.org>,
<linux-arm-kernel@lists.infradead.org>,
<linux-sunxi@lists.linux.dev>, <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] drm/sun4i: uncouple DSI dotclock divider from TCON0_DCLK_REG
Date: Wed, 05 Apr 2023 14:34:11 +0200 [thread overview]
Message-ID: <CROTQHUM88W0.2URPO95U5ZMS5@void.crly.cz> (raw)
In-Reply-To: <20230329195802.veybo3367zifw77n@penduick>
Hello Maxime,
On Wed Mar 29, 2023 at 9:58 PM CEST, Maxime Ripard wrote:
> > In order to preserve semantic correctness however, I propose to preface
> > the change with a patch that renames sun4i_dotclock and tcon-pixel-clock
> > such that dot/pixel is replaced with d/data. What do you think?
>
> I don't think it's exposed to the userspace in any way so it makes sense to me
>
Here's a new series that includes those renames:
<https://lore.kernel.org/all/20230331110245.43527-1-me@crly.cz/>
It turns out however that the new dclk rates can't be set exactly as
requested without touching pll-video0*, tcon0 now therefore gets
reparented from pll-mipi to pll-video0-2x which, as it further turns
out, breaks DSI. While simply forbidding the video0-2x mux option seems
to me as the right way to go because there's not much use for it with
non-DSI interfaces either besides the opportunity to power pll-mipi
down, I'd like to run by you first.
Kind regards,
Roman
* As pll-mipi doesn't have CLK_SET_RATE_PARENT flag set, pll-video0
retains its boot-time rate of 294 MHz set by sunxi-dw-hdmi driver
in u-boot. Why 294 MHz (as opposed to the default rate of 297 MHz)?
The driver actually asks for 297 MHz, clock_set_pll3 rounds it to
294 MHz though because it limits itself to 6 MHz steps.
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2023-04-05 12:34 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-20 16:16 [PATCH] drm/sun4i: uncouple DSI dotclock divider from TCON0_DCLK_REG Roman Beranek
2023-03-20 16:16 ` Roman Beranek
2023-03-20 16:16 ` Roman Beranek
2023-03-21 14:56 ` Maxime Ripard
2023-03-21 14:56 ` Maxime Ripard
2023-03-21 14:56 ` Maxime Ripard
2023-03-21 16:50 ` Roman Beranek
2023-03-21 16:50 ` Roman Beranek
2023-03-21 16:50 ` Roman Beranek
2023-03-21 20:53 ` Roman Beranek
2023-03-21 20:53 ` Roman Beranek
2023-03-21 20:53 ` Roman Beranek
2023-03-27 20:21 ` Maxime Ripard
2023-03-27 20:21 ` Maxime Ripard
2023-03-27 20:21 ` Maxime Ripard
2023-03-25 11:40 ` Frank Oltmanns
2023-03-25 11:40 ` Frank Oltmanns
2023-03-25 11:40 ` Frank Oltmanns
2023-03-27 20:20 ` Maxime Ripard
2023-03-27 20:20 ` Maxime Ripard
2023-03-27 20:20 ` Maxime Ripard
2023-03-27 23:48 ` Roman Beranek
2023-03-27 23:48 ` Roman Beranek
2023-03-27 23:48 ` Roman Beranek
2023-03-29 19:58 ` Maxime Ripard
2023-03-29 19:58 ` Maxime Ripard
2023-03-29 19:58 ` Maxime Ripard
2023-03-30 4:45 ` Frank Oltmanns
2023-03-30 4:45 ` Frank Oltmanns
2023-03-30 4:45 ` Frank Oltmanns
2023-03-31 5:36 ` Roman Beranek
2023-03-31 5:36 ` Roman Beranek
2023-03-31 5:36 ` Roman Beranek
2023-04-05 12:34 ` Roman Beranek [this message]
2023-04-05 12:34 ` Roman Beranek
2023-04-05 12:34 ` Roman Beranek
2023-04-05 15:03 ` Maxime Ripard
2023-04-05 15:03 ` Maxime Ripard
2023-04-05 15:03 ` Maxime Ripard
2023-04-12 7:14 ` Roman Beranek
2023-04-12 7:14 ` Roman Beranek
2023-04-12 7:14 ` Roman Beranek
2023-04-12 14:09 ` Maxime Ripard
2023-04-12 14:09 ` Maxime Ripard
2023-04-12 14:09 ` Maxime Ripard
2023-04-08 7:07 ` Jernej Škrabec
2023-04-08 7:07 ` Jernej Škrabec
2023-04-08 7:07 ` Jernej Škrabec
2023-04-12 1:22 ` Roman Beranek
2023-04-12 1:22 ` Roman Beranek
2023-04-12 1:22 ` Roman Beranek
2023-03-28 19:28 ` Frank Oltmanns
2023-03-28 19:28 ` Frank Oltmanns
2023-03-28 19:28 ` Frank Oltmanns
2023-03-29 19:56 ` Maxime Ripard
2023-03-29 19:56 ` Maxime Ripard
2023-03-29 19:56 ` Maxime Ripard
2023-03-30 4:41 ` Frank Oltmanns
2023-03-30 4:41 ` Frank Oltmanns
2023-03-30 4:41 ` Frank Oltmanns
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