linux-kernel - Re: [PATCH v2] drm/bridge: cdns-dsi: Split pm_ops into runtime_pm and system

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <3ce98440-7b8d-4db3-afa3-64890da4a8cf@ti.com>
Date: Tue, 13 Jan 2026 15:23:09 +0530
From: "Kumar, Udit" <u-kumar1@...com>
To: Abhash Kumar Jha <a-kumar2@...com>, <andrzej.hajda@...el.com>,
	<neil.armstrong@...aro.org>, <rfoss@...nel.org>, <mripard@...nel.org>,
	<tzimmermann@...e.de>, <airlied@...il.com>, <simona@...ll.ch>,
	<devarsht@...com>
CC: <linux-kernel@...r.kernel.org>, <dri-devel@...ts.freedesktop.org>,
	<Laurent.pinchart@...asonboard.com>, <jonas@...boo.se>,
	<jernej.skrabec@...il.com>, <s-jain1@...com>, <p-mantena@...com>,
	<aradhya.bhatia@...ux.dev>, <tomi.valkeinen@...asonboard.com>,
	<p.zabel@...gutronix.de>, <u-kumar1@...com>
Subject: Re: [PATCH v2] drm/bridge: cdns-dsi: Split pm_ops into runtime_pm and
 system_sleep ops


On 1/12/2026 2:42 PM, Abhash Kumar Jha wrote:
> If runtime-pm has already suspended the device and a system suspend
> occurs, then we see a kernel crash when disabling and unpreparing the
> clocks.
>
> Use pm_runtime_force_suspend/resume in system_sleep pm callbacks to let
> runtime-pm take care of the coordination between system suspend and
> itself. This ensures that they do not interfere with each other.
>
> Signed-off-by: Abhash Kumar Jha <a-kumar2@...com>
> ---
> Hi,
>
> If a device is runtime_pm suspended and a system wide suspend is triggered,
> we see a kernel crash. Hence split the power management ops into separate
> system_sleep and runtime_pm ops.
>
> Changes in v2:
> - Improve the commit description and subject.
> - Link to v1: https://lore.kernel.org/all/20260109060312.2853133-1-a-kumar2@ti.com/
>
> Thanks,
> Abhash
>
>   .../gpu/drm/bridge/cadence/cdns-dsi-core.c    | 32 +++++++++++++------
>   1 file changed, 23 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c b/drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c
> index 09b289f0fcbf..25eaf0192013 100644
> --- a/drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c
> +++ b/drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c
> @@ -1230,7 +1230,18 @@ static const struct mipi_dsi_host_ops cdns_dsi_ops = {
>   	.transfer = cdns_dsi_transfer,
>   };
>   
> -static int __maybe_unused cdns_dsi_resume(struct device *dev)
> +static int cdns_dsi_runtime_suspend(struct device *dev)
> +{
> +	struct cdns_dsi *dsi = dev_get_drvdata(dev);
> +
> +	clk_disable_unprepare(dsi->dsi_sys_clk);
> +	clk_disable_unprepare(dsi->dsi_p_clk);
> +	reset_control_assert(dsi->dsi_p_rst);
> +
> +	return 0;
> +}
> +

Reviewed-by: Udit Kumar <u-kumar1@...com>


> +static int cdns_dsi_runtime_resume(struct device *dev)
>   {
>   	struct cdns_dsi *dsi = dev_get_drvdata(dev);
>   
> @@ -1241,18 +1252,21 @@ static int __maybe_unused cdns_dsi_resume(struct device *dev)
>   	return 0;
>   }
>   
> -static int __maybe_unused cdns_dsi_suspend(struct device *dev)
> +static int cdns_dsi_suspend(struct device *dev)
>   {
> -	struct cdns_dsi *dsi = dev_get_drvdata(dev);
> +	return pm_runtime_force_suspend(dev);
> +}
>   
> -	clk_disable_unprepare(dsi->dsi_sys_clk);
> -	clk_disable_unprepare(dsi->dsi_p_clk);
> -	reset_control_assert(dsi->dsi_p_rst);
> -	return 0;
> +static int cdns_dsi_resume(struct device *dev)
> +{
> +	return pm_runtime_force_resume(dev);
>   }
>   
> -static UNIVERSAL_DEV_PM_OPS(cdns_dsi_pm_ops, cdns_dsi_suspend, cdns_dsi_resume,
> -			    NULL);
> +static const struct dev_pm_ops cdns_dsi_pm_ops = {
> +	SET_RUNTIME_PM_OPS(cdns_dsi_runtime_suspend,
> +			cdns_dsi_runtime_resume, NULL)
> +	SET_SYSTEM_SLEEP_PM_OPS(cdns_dsi_suspend, cdns_dsi_resume)
> +};
>   
>   static int cdns_dsi_drm_probe(struct platform_device *pdev)
>   {