Linux clock framework development
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From: Maxime Ripard <maxime.ripard@bootlin.com>
To: Jernej Skrabec <jernej.skrabec@siol.net>
Cc: wens@csie.org, mturquette@baylibre.com, sboyd@kernel.org,
	linux-arm-kernel@lists.infradead.org, linux-clk@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-sunxi@googlegroups.com
Subject: Re: [PATCH 0/5] Set max rate for video PLLs
Date: Mon, 20 Aug 2018 15:36:47 +0200	[thread overview]
Message-ID: <20180820133647.vpj7p36ir334g4am@flea> (raw)
In-Reply-To: <20180809165217.30680-1-jernej.skrabec@siol.net>

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On Thu, Aug 09, 2018 at 06:52:12PM +0200, Jernej Skrabec wrote:
> This patch series implement maximum rate constraint for video PLLs,
> because it is possible to set higher PLL rate that is actually
> supported in HW.
> 
> Issue became apparent when user reported non-working monitor connected
> to board with H5 SoC. Native monitor resolution in this case was
> 2560x1080, with 185580 kHz pixel clock. Clock subsystem found out that
> best matching pixel clock can be generated if video PLL is set to 2040
> MHz, which is way out of specs for PLL. With this patch series applied,
> everything worked just fine, with slightly higher rate error, but within
> working limits for PLL and HDMI.
> 
> I'm not sure if "Fixes" tag should be added. It solves real world
> problem, but there was nothing wrongly implemented, just upper limit
> is missing.
> 
> While user reported that these patches solve the issue on H5, I added
> similar fixes for other SoCs too. Since I don't have such monitor,
> I only tested if board boots up and if HDMI works (H3, R40 and A83T).

Queued for 4.20, thanks!
Maxime

-- 
Maxime Ripard, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com

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      parent reply	other threads:[~2018-08-20 16:52 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-08-09 16:52 [PATCH 0/5] Set max rate for video PLLs Jernej Skrabec
2018-08-09 16:52 ` [PATCH 1/5] clk: sunxi-ng: Add maximum rate constraint to NM PLLs Jernej Skrabec
2018-08-09 16:52 ` [PATCH 2/5] clk: sunxi-ng: h3/h5: Add max. rate constraint to pll-video Jernej Skrabec
2018-08-09 16:52 ` [PATCH 3/5] clk: sunxi-ng: r40: Add max. rate constraint to video PLLs Jernej Skrabec
2018-08-09 16:52 ` [PATCH 4/5] clk: sunxi-ng: nkmp: Add constraint for maximum rate Jernej Skrabec
2018-08-09 16:52 ` [PATCH 5/5] clk: sunxi-ng: a83t: Add max. rate constraint to video PLLs Jernej Skrabec
2018-08-20 13:36 ` Maxime Ripard [this message]

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