LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Chris Morgan <macroalpha82@gmail.com>
To: andriy.shevchenko@linux.intel.com
Cc: abel.vesa@nxp.com, festevam@gmail.com, heiko@sntech.de,
	kernel@pengutronix.de, lee.jones@linaro.org, lenb@kernel.org,
	linux-acpi@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-clk@vger.kernel.org, linux-imx@nxp.com,
	linux-kernel@vger.kernel.org, linux-rockchip@lists.infradead.org,
	mturquette@baylibre.com, rafael.j.wysocki@intel.com,
	rjw@rjwysocki.net, s.hauer@pengutronix.de, sboyd@kernel.org,
	shawnguo@kernel.org, zhangqing@rock-chips.com,
	Chris Morgan <macromorgan@hotmail.com>
Subject: Re: [PATCH v4 1/4] clk: fractional-divider: Export approximation algorithm to the CCF users
Date: Tue,  7 Sep 2021 10:44:00 -0500	[thread overview]
Message-ID: <20210907154400.26656-1-macroalpha82@gmail.com> (raw)
In-Reply-To: <20210812170025.67074-1-andriy.shevchenko@linux.intel.com>

From: Chris Morgan <macromorgan@hotmail.com>

Unfortunately, I can confirm this breaks the DSI panel on the Rockchip
PX30 (and possibly other SoCs). Tested on my Odroid Go Advance. When
I revert 4e7cf74fa3b2 "clk: fractional-divider: Export approximation
algorithm to the CCF users" and 928f9e268611 "clk: fractional-divider:
Hide clk_fractional_divider_ops from wide audience" the panel begins
working again as expected on the master branch.

It looks like an assumption is made in the vop_crtc_mode_fixup()
function in the rockchip_drm_vop.c that gets broken with this change.
Specifically, the function says in the comments "When DRM gives us a
mode, we should add 999 Hz to it.". I believe this is no longer true
after this clk change, and when I remove the + 999 from the function
the DSI panel works again. Note that I do not know the implications
of removing this 999 aside from that it fixes the DSI panel on my
PX30 after this change, so I don't know if it's a positive change
or not.

Thank you.

  parent reply	other threads:[~2021-09-07 15:44 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-12 17:00 Andy Shevchenko
2021-08-12 17:00 ` [PATCH v4 2/4] clk: fractional-divider: Hide clk_fractional_divider_ops from wide audience Andy Shevchenko
2021-08-12 17:00 ` [PATCH v4 3/4] clk: fractional-divider: Introduce POWER_OF_TWO_PS flag Andy Shevchenko
2021-08-12 17:00 ` [PATCH v4 4/4] clk: fractional-divider: Document the arithmetics used behind the code Andy Shevchenko
     [not found] ` <162879819529.19113.6409882476721828944@swboyd.mtv.corp.google.com>
2021-08-13  9:43   ` [PATCH v4 1/4] clk: fractional-divider: Export approximation algorithm to the CCF users Andy Shevchenko
2021-08-17 12:45     ` Andy Shevchenko
2021-09-07 15:44 ` Chris Morgan [this message]
2021-09-07 17:54   ` Andy Shevchenko
2021-09-07 18:06     ` Andy Shevchenko
     [not found]       ` <SN6PR06MB534203466EA3D4E22858479FA5D49@SN6PR06MB5342.namprd06.prod.outlook.com>
2021-09-08 10:52         ` Andy Shevchenko

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20210907154400.26656-1-macroalpha82@gmail.com \
    --to=macroalpha82@gmail.com \
    --cc=abel.vesa@nxp.com \
    --cc=andriy.shevchenko@linux.intel.com \
    --cc=festevam@gmail.com \
    --cc=heiko@sntech.de \
    --cc=kernel@pengutronix.de \
    --cc=lee.jones@linaro.org \
    --cc=lenb@kernel.org \
    --cc=linux-acpi@vger.kernel.org \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-clk@vger.kernel.org \
    --cc=linux-imx@nxp.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-rockchip@lists.infradead.org \
    --cc=macromorgan@hotmail.com \
    --cc=mturquette@baylibre.com \
    --cc=rafael.j.wysocki@intel.com \
    --cc=rjw@rjwysocki.net \
    --cc=s.hauer@pengutronix.de \
    --cc=sboyd@kernel.org \
    --cc=shawnguo@kernel.org \
    --cc=zhangqing@rock-chips.com \
    --subject='Re: [PATCH v4 1/4] clk: fractional-divider: Export approximation algorithm to the CCF users' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).