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From: Thomas Gleixner <tglx@linutronix.de>
To: Marc Zyngier <maz@kernel.org>
Cc: Frank Wunderlich <frank-w@public-files.de>,
	Ryder Lee <ryder.lee@mediatek.com>,
	linux-mediatek@lists.infradead.org,
	Frank Wunderlich <linux@fw-web.de>,
	linux-kernel@vger.kernel.org,
	Matthias Brugger <matthias.bgg@gmail.com>,
	linux-pci@vger.kernel.org, Bjorn Helgaas <bhelgaas@google.com>
Subject: Re: Aw: Re: [PATCH] pci: mediatek: fix warning in msi.h
Date: Tue, 03 Nov 2020 11:16:56 +0100	[thread overview]
Message-ID: <87o8ke7njb.fsf@nanos.tec.linutronix.de> (raw)
In-Reply-To: <901c5eb8bbaa3fe53ddc8f65917e48ef@kernel.org>

On Tue, Nov 03 2020 at 09:54, Marc Zyngier wrote:
> On 2020-11-02 22:18, Thomas Gleixner wrote:
>> On Mon, Nov 02 2020 at 17:16, Thomas Gleixner wrote:
>>> On Mon, Nov 02 2020 at 11:30, Marc Zyngier wrote:
>>>> --- a/drivers/pci/probe.c
>>>> +++ b/drivers/pci/probe.c
>>>> @@ -871,6 +871,8 @@ static void pci_set_bus_msi_domain(struct pci_bus
>>>> *bus)
>>>>   		d = pci_host_bridge_msi_domain(b);
>>>> 
>>>>   	dev_set_msi_domain(&bus->dev, d);
>>>> +	if (!d)
>>>> +		bus->bus_flags |= PCI_BUS_FLAGS_NO_MSI;
>>> 
>>> Hrm, that might break legacy setups (no irqdomain support). I'd rather
>>> prefer to explicitly tell the pci core at host registration time.
>> 
>> s/might break/ breaks /     Just validated :)
>
> For my own edification, can you point me to the failing case?

Any architecture which selects PCI_MSI_ARCH_FALLBACKS and does not have
irqdomain support runs into:

	if (!d)
		bus->bus_flags |= PCI_BUS_FLAGS_NO_MSI;

which in turn makes pci_msi_supported() return 0 and consequently makes
pci_enable_msi[x]() fail.

Thanks,

        tglx

WARNING: multiple messages have this Message-ID (diff)
From: Thomas Gleixner <tglx@linutronix.de>
To: Marc Zyngier <maz@kernel.org>
Cc: Ryder Lee <ryder.lee@mediatek.com>,
	Frank Wunderlich <frank-w@public-files.de>,
	linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
	Bjorn Helgaas <bhelgaas@google.com>,
	linux-mediatek@lists.infradead.org,
	Matthias Brugger <matthias.bgg@gmail.com>,
	Frank Wunderlich <linux@fw-web.de>
Subject: Re: Aw: Re: [PATCH] pci: mediatek: fix warning in msi.h
Date: Tue, 03 Nov 2020 11:16:56 +0100	[thread overview]
Message-ID: <87o8ke7njb.fsf@nanos.tec.linutronix.de> (raw)
In-Reply-To: <901c5eb8bbaa3fe53ddc8f65917e48ef@kernel.org>

On Tue, Nov 03 2020 at 09:54, Marc Zyngier wrote:
> On 2020-11-02 22:18, Thomas Gleixner wrote:
>> On Mon, Nov 02 2020 at 17:16, Thomas Gleixner wrote:
>>> On Mon, Nov 02 2020 at 11:30, Marc Zyngier wrote:
>>>> --- a/drivers/pci/probe.c
>>>> +++ b/drivers/pci/probe.c
>>>> @@ -871,6 +871,8 @@ static void pci_set_bus_msi_domain(struct pci_bus
>>>> *bus)
>>>>   		d = pci_host_bridge_msi_domain(b);
>>>> 
>>>>   	dev_set_msi_domain(&bus->dev, d);
>>>> +	if (!d)
>>>> +		bus->bus_flags |= PCI_BUS_FLAGS_NO_MSI;
>>> 
>>> Hrm, that might break legacy setups (no irqdomain support). I'd rather
>>> prefer to explicitly tell the pci core at host registration time.
>> 
>> s/might break/ breaks /     Just validated :)
>
> For my own edification, can you point me to the failing case?

Any architecture which selects PCI_MSI_ARCH_FALLBACKS and does not have
irqdomain support runs into:

	if (!d)
		bus->bus_flags |= PCI_BUS_FLAGS_NO_MSI;

which in turn makes pci_msi_supported() return 0 and consequently makes
pci_enable_msi[x]() fail.

Thanks,

        tglx

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  reply	other threads:[~2020-11-03 10:17 UTC|newest]

Thread overview: 62+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-31 14:03 [PATCH] pci: mediatek: fix warning in msi.h Frank Wunderlich
2020-10-31 14:03 ` Frank Wunderlich
2020-10-31 21:49 ` Thomas Gleixner
2020-10-31 21:49   ` Thomas Gleixner
2020-11-01  9:25   ` Frank Wunderlich
2020-11-01  9:25     ` Frank Wunderlich
2020-11-01 11:17     ` Thomas Gleixner
2020-11-01 11:17       ` Thomas Gleixner
2020-11-01 11:43     ` Marc Zyngier
2020-11-01 11:43       ` Marc Zyngier
2020-11-01 15:58       ` Aw: " Frank Wunderlich
2020-11-01 15:58         ` Frank Wunderlich
2020-11-01 17:54       ` Ryder Lee
2020-11-01 17:54         ` Ryder Lee
2020-11-01 18:27         ` Aw: " Frank Wunderlich
2020-11-01 18:27           ` Frank Wunderlich
2020-11-01 21:47           ` Marc Zyngier
2020-11-01 21:47             ` Marc Zyngier
2020-11-01 22:27             ` Thomas Gleixner
2020-11-01 22:27               ` Thomas Gleixner
2020-11-02 11:30               ` Marc Zyngier
2020-11-02 11:30                 ` Marc Zyngier
2020-11-02 11:56                 ` Aw: " Frank Wunderlich
2020-11-02 11:56                   ` Frank Wunderlich
2020-11-02 13:58                   ` Marc Zyngier
2020-11-02 13:58                     ` Marc Zyngier
2020-11-02 14:27                     ` Aw: " Frank Wunderlich
2020-11-02 14:27                       ` Frank Wunderlich
2020-11-02 16:16                 ` Aw: " Thomas Gleixner
2020-11-02 16:16                   ` Thomas Gleixner
2020-11-02 22:18                   ` Thomas Gleixner
2020-11-02 22:18                     ` Thomas Gleixner
2020-11-03  9:54                     ` Marc Zyngier
2020-11-03  9:54                       ` Marc Zyngier
2020-11-03 10:16                       ` Thomas Gleixner [this message]
2020-11-03 10:16                         ` Thomas Gleixner
2020-11-03 10:29                         ` Marc Zyngier
2020-11-03 10:29                           ` Marc Zyngier
2020-11-04 16:49                         ` Aw: " Frank Wunderlich
2020-11-04 16:49                           ` Frank Wunderlich
2020-11-04 23:14                           ` Thomas Gleixner
2020-11-04 23:14                             ` Thomas Gleixner
2020-11-05  9:20                             ` Marc Zyngier
2020-11-05  9:20                               ` Marc Zyngier
2020-11-05 13:59                               ` Aw: " Frank Wunderlich
2020-11-05 13:59                                 ` Frank Wunderlich
2020-11-05 23:00                               ` Aw: " Thomas Gleixner
2020-11-05 23:00                                 ` Thomas Gleixner
2020-11-06  9:43                                 ` Marc Zyngier
2020-11-06  9:43                                   ` Marc Zyngier
2020-11-21 16:12                                   ` Aw: " Frank Wunderlich
2020-11-21 16:12                                     ` Frank Wunderlich
2021-01-03 13:08                                     ` Frank Wunderlich
2021-01-03 13:08                                       ` Frank Wunderlich
2021-02-02 16:21                                   ` Frank Wunderlich
2021-02-02 16:21                                     ` Frank Wunderlich
2020-11-03 10:31                       ` Aw: " Thomas Gleixner
2020-11-03 10:31                         ` Thomas Gleixner
2020-11-03 11:41                         ` Marc Zyngier
2020-11-03 11:41                           ` Marc Zyngier
2020-11-03 14:23                           ` Thomas Gleixner
2020-11-03 14:23                             ` Thomas Gleixner

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