From: Marek Vasut <marex@denx.de>
To: Peng Fan <peng.fan@oss.nxp.com>,
abelvesa@kernel.org, Lucas Stach <l.stach@pengutronix.de>,
ulf.hansson@linaro.org, linux-pm@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, aisheng.dong@nxp.com,
kernel@pengutronix.de, Shawn Guo <shawnguo@kernel.org>,
s.hauer@pengutronix.de, festevam@gmail.com,
Stephen Boyd <sboyd@kernel.org>
Subject: Re: Help: i.MX8MP AUDIOMIX BLK-CTRL CLK driver support
Date: Mon, 26 Sep 2022 02:04:31 +0200 [thread overview]
Message-ID: <09bb716b-1f6b-c422-8469-fd2a0ac9f946@denx.de> (raw)
In-Reply-To: <d23cacb6-4914-7eba-ed6e-c8490b9b771a@oss.nxp.com>
On 9/23/22 05:41, Peng Fan wrote:
> Hi All,
Hi,
> I would start a discussion about the A/B B/A lock issue when make
> audiomix blk ctrl function as clk provider.
>
> I not have good idea on this, hope you have any suggestions.
>
> major issue is: the blk ctrl clk has a power domain supplier
> The power domain supplier also use clk API to prepare_enable clks.
> The blk ctrl clk driver has runtime pm enabled.
>
> The NXP downstream:
> The dts:
> https://github.com/nxp-imx/linux-imx/blob/lf-5.15.y/arch/arm64/boot/dts/freescale/imx8mp.dtsi#L1872
>
> The driver:
> https://github.com/nxp-imx/linux-imx/blob/lf-5.15.y/drivers/clk/imx/clk-imx8mp.c
> https://github.com/nxp-imx/linux-imx/blob/lf-5.15.y/drivers/clk/imx/clk-blk-ctrl.c
>
> Note: The following log was reproduced with NXP downstream. For upstream
> I think we have similar issue if we still take audiomix blk ctrl as clk
> driver. Because the gpcv2 also use clk prepare enable API.
> 1. deadlock 1:
> Callchain after enable some lock debug:
> clk_ignore_unused will use lock seq: take prepare lock, take blk-ctrl
> parent power domain genpd lock
> genpd_power_off_work_fun will use lock seq: take the power domain genpd
> lock, take prepare lock.
There is also this driver which does not suffer from the problem, at
least I didn't trigger it while using it for months:
https://patchwork.kernel.org/project/linux-clk/patch/20220625013235.710346-3-marex@denx.de/
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next prev parent reply other threads:[~2022-09-26 0:06 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-23 3:41 Help: i.MX8MP AUDIOMIX BLK-CTRL CLK driver support Peng Fan
2022-09-23 8:18 ` Lucas Stach
2022-09-27 9:36 ` Peng Fan
2022-09-26 0:04 ` Marek Vasut [this message]
2022-09-27 3:26 ` Peng Fan
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