From: Mika Westerberg <mika.westerberg@linux.intel.com>
To: Mario Limonciello <mario.limonciello@amd.com>
Cc: bhelgaas@google.com, lukas@wunner.de,
linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org
Subject: Re: [PATCH] PCI: Make d3cold_allowed sysfs attribute read only
Date: Tue, 3 Oct 2023 12:44:07 +0300 [thread overview]
Message-ID: <20231003094407.GG3208943@black.fi.intel.com> (raw)
In-Reply-To: <20231002181025.82746-1-mario.limonciello@amd.com>
On Mon, Oct 02, 2023 at 01:10:25PM -0500, Mario Limonciello wrote:
> Before d3cold was stable userspace was allowed to influence the kernel's
> decision of whether to enable d3cold for a device by a sysfs file
> `d3cold_allowed`. This potentially allows userspace to break the suspend
> for the system.
>
> For debugging purposes `pci_port_pm=` can be used to control whether
> a PCI port will go into D3cold and runtime PM can be turned off by
> sysfs on PCI end points.
>
> Change the sysfs attribute to read-only and simplify the internal kernel
> logic to avoid needing to store the userspace request.
I wonder if this ends up breaking some userspace apps? Not objecting
though, just wanted to mention ;-)
One thing we could do is to taint the kernel or log a warning if
userspace touches this but allow it to do so.
next prev parent reply other threads:[~2023-10-03 9:44 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-02 18:10 [PATCH] PCI: Make d3cold_allowed sysfs attribute read only Mario Limonciello
2023-10-03 9:44 ` Mika Westerberg [this message]
2023-10-03 16:30 ` Mario Limonciello
2023-10-03 20:07 ` Lukas Wunner
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