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.
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next prev parent reply other threads:[~2021-09-07 15:46 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-12 17:00 [PATCH v4 1/4] clk: fractional-divider: Export approximation algorithm to the CCF users 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 19:56 ` Stephen Boyd
2021-08-12 17:00 ` [PATCH v4 3/4] clk: fractional-divider: Introduce POWER_OF_TWO_PS flag Andy Shevchenko
2021-08-12 19:56 ` Stephen Boyd
2021-08-12 17:00 ` [PATCH v4 4/4] clk: fractional-divider: Document the arithmetics used behind the code Andy Shevchenko
2021-08-12 19:56 ` Stephen Boyd
2021-08-12 19:56 ` [PATCH v4 1/4] clk: fractional-divider: Export approximation algorithm to the CCF users Stephen Boyd
2021-08-13 9:43 ` 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
2021-09-08 2:17 ` Chris Morgan
2021-09-08 10:52 ` Andy Shevchenko
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