Re: [PATCH v4 03/68] clk: Move no reparent case into a separate function

[Marek Szyprowski <m.szyprowski@samsung.com>]

On 13.06.2023 13:15, Marek Szyprowski wrote:
> On 05.05.2023 13:25, Maxime Ripard wrote:
>> From: Stephen Boyd <sboyd@kernel.org>
>>
>> We'll need to turn the code in clk_mux_determine_rate_flags() to deal
>> with CLK_SET_RATE_NO_REPARENT into a helper clock drivers will be able
>> to use if they don't want to allow reparenting.
>>
>> Cc: Abel Vesa <abelvesa@kernel.org>
>> Cc: Alessandro Zummo <a.zummo@towertech.it>
>> Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
>> Cc: Alexandre Torgue <alexandre.torgue@foss.st.com>
>> Cc: "Andreas Färber" <afaerber@suse.de>
>> Cc: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
>> Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
>> Cc: Charles Keepax <ckeepax@opensource.cirrus.com>
>> Cc: Chen-Yu Tsai <wens@csie.org>
>> Cc: Chen-Yu Tsai <wenst@chromium.org>
>> Cc: Chunyan Zhang <zhang.lyra@gmail.com>
>> Cc: Claudiu Beznea <claudiu.beznea@microchip.com>
>> Cc: Daniel Vetter <daniel@ffwll.ch>
>> Cc: David Airlie <airlied@gmail.com>
>> Cc: David Lechner <david@lechnology.com>
>> Cc: Dinh Nguyen <dinguyen@kernel.org>
>> Cc: Fabio Estevam <festevam@gmail.com>
>> Cc: Geert Uytterhoeven <geert+renesas@glider.be>
>> Cc: Jaroslav Kysela <perex@perex.cz>
>> Cc: Jernej Skrabec <jernej.skrabec@gmail.com>
>> Cc: Jonathan Hunter <jonathanh@nvidia.com>
>> Cc: Kishon Vijay Abraham I <kishon@kernel.org>
>> Cc: Liam Girdwood <lgirdwood@gmail.com>
>> Cc: Linus Walleij <linus.walleij@linaro.org>
>> Cc: Luca Ceresoli <luca.ceresoli@bootlin.com>
>> Cc: Manivannan Sadhasivam <mani@kernel.org>
>> Cc: Mark Brown <broonie@kernel.org>
>> Cc: Markus Schneider-Pargmann <msp@baylibre.com>
>> Cc: Max Filippov <jcmvbkbc@gmail.com>
>> Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
>> Cc: Mikko Perttunen <mperttunen@nvidia.com>
>> Cc: Miles Chen <miles.chen@mediatek.com>
>> Cc: Nicolas Ferre <nicolas.ferre@microchip.com>
>> Cc: Orson Zhai <orsonzhai@gmail.com>
>> Cc: Paul Cercueil <paul@crapouillou.net>
>> Cc: Peng Fan <peng.fan@nxp.com>
>> Cc: Peter De Schrijver <pdeschrijver@nvidia.com>
>> Cc: Prashant Gaikwad <pgaikwad@nvidia.com>
>> Cc: Richard Fitzgerald <rf@opensource.cirrus.com>
>> Cc: Samuel Holland <samuel@sholland.org>
>> Cc: Sascha Hauer <s.hauer@pengutronix.de>
>> Cc: Sekhar Nori <nsekhar@ti.com>
>> Cc: Shawn Guo <shawnguo@kernel.org>
>> Cc: Takashi Iwai <tiwai@suse.com>
>> Cc: Thierry Reding <thierry.reding@gmail.com>
>> Cc: Ulf Hansson <ulf.hansson@linaro.org>
>> Cc: Vinod Koul <vkoul@kernel.org>
>> Cc: dri-devel@lists.freedesktop.org
>> Cc: linux-actions@lists.infradead.org
>> Cc: linux-arm-kernel@lists.infradead.org
>> Cc: linux-mips@vger.kernel.org
>> Cc: linux-phy@lists.infradead.org
>> Cc: linux-renesas-soc@vger.kernel.org
>> Cc: linux-rtc@vger.kernel.org
>> Cc: linux-stm32@st-md-mailman.stormreply.com
>> Cc: linux-sunxi@lists.linux.dev
>> Cc: linux-tegra@vger.kernel.org
>> Cc: NXP Linux Team <linux-imx@nxp.com>
>> Cc: patches@opensource.cirrus.com
>> Cc: Pengutronix Kernel Team <kernel@pengutronix.de>
>> Signed-off-by: Stephen Boyd <sboyd@kernel.org>
>> Signed-off-by: Maxime Ripard <maxime@cerno.tech>
>> ---
>
> This patch landed in today's linux-next as commit 1b4e99fda73f ("clk: 
> Move no reparent case into a separate function"). Unfortunately it 
> causes serious regression of some of my test boards. Namely Exynos3250 
> based boards are so slow after it, that my test scripts fail with a 
> timeout waiting for them to finish booting. I will try to debug this 
> later in the evening to check what has happened that some clocks got 
> very low rate.
>
I just got a few spare minutes, so I decided to take a look into this 
issue. The following change fixed my problem:

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index ffc9f03840b7..7ac9f7a8cb84 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -629,6 +629,7 @@ clk_core_determine_rate_no_reparent(struct clk_hw *hw,
                 best = clk_core_get_rate_nolock(core);
         }

+       req->best_parent_rate = best;
         req->rate = best;

         return 0;

best_parent_rate is still being used somewhere in the code and needs to 
be updated regardless of the CLK_SET_RATE_NO_REPARENT flag.

 > ...

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland