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From: Lukas Wunner <lukas@wunner.de>
To: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>,
	"Rafael J. Wysocki" <rjw@rjwysocki.net>,
	Kedar A Dongre <kedar.a.dongre@intel.com>,
	linux-pci@vger.kernel.org, linux-acpi@vger.kernel.org
Subject: Re: [PATCH] PCI: Blacklist power management of Gigabyte X299 DESIGNARE EX PCIe ports
Date: Wed, 5 Dec 2018 10:48:18 +0100	[thread overview]
Message-ID: <20181205094818.jmdy2mg6b6is7jy3@wunner.de> (raw)
In-Reply-To: <20181205092034.GI2469@lahna.fi.intel.com>

On Wed, Dec 05, 2018 at 11:20:34AM +0200, Mika Westerberg wrote:
> On Tue, Dec 04, 2018 at 09:40:49PM +0100, Lukas Wunner wrote:
> > > I wonder if our pci_bridge_d3_possible() heuristics would need to be
> > > refined somehow? At least if this blacklist starts growing.
> > 
> > We do blacklist such non-native hotplug ports, but of course only if
> > the Hot-Plug Capable bit is set:
> > 
> > 	/*
> > 	 * Hotplug ports handled by firmware in System Management Mode
> > 	 * may not be put into D3 by the OS (Thunderbolt on non-Macs).
> > 	 */
> > 	if (bridge->is_hotplug_bridge && !pciehp_is_native(bridge))
> > 		return false;
> > 
> > I guess your question boils down to, is there any better way to recognize
> > ports which are handled by the platform firmware?
> > Does acpiphp bind to this port?
> 
> It does, yes but AFAIK it binds to any PCI bus (bridge) if it has an
> ACPI companion.

Does the root port have a _RMV and/or _SUN object?  We could e.g.
disallow runtime PM for any bridge with _RMV present and the HPC
bit not set in the Slot Capabilities.

This could be checked by extending acpi_pci_bridge_d3() to return
either true, false or a "don't know" value.  Or by adding another
platform_pci_bridge_no_d3() hook.

Thanks,

Lukas

  reply	other threads:[~2018-12-05  9:48 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-12-04 11:20 [PATCH] PCI: Blacklist power management of Gigabyte X299 DESIGNARE EX PCIe ports Mika Westerberg
2018-12-04 17:55 ` Rafael J. Wysocki
2018-12-04 18:34   ` Mika Westerberg
2018-12-04 20:40 ` Lukas Wunner
2018-12-05  9:20   ` Mika Westerberg
2018-12-05  9:48     ` Lukas Wunner [this message]
2018-12-05 10:40       ` Mika Westerberg
2018-12-05 13:22         ` Lukas Wunner
2018-12-05 13:46           ` Mika Westerberg
2018-12-14  9:24 ` Mika Westerberg
2018-12-17 20:28 ` Bjorn Helgaas
2018-12-18  8:55   ` Mika Westerberg
2018-12-18 20:58     ` Bjorn Helgaas
2018-12-19 13:23       ` Mika Westerberg
2018-12-19 14:45         ` Bjorn Helgaas
2018-12-19 15:15           ` Mika Westerberg
2018-12-19 17:09             ` Lukas Wunner
2018-12-20 10:06               ` Mika Westerberg
2018-12-20 10:23                 ` Rafael J. Wysocki

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