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From: Greg KH <greg@kroah.com>
To: Pavel Machek <pavel@ucw.cz>
Cc: kernel list <linux-kernel@vger.kernel.org>,
	joe.lawrence@stratus.com, myron.stowe@redhat.com,
	bhelgaas@google.com
Subject: Re: /sys/module/pcie_aspm/parameters/policy not writable?
Date: Tue, 9 Jul 2013 09:37:26 -0700	[thread overview]
Message-ID: <20130709163726.GA11809@kroah.com> (raw)
In-Reply-To: <20130709094906.GA3870@amd.pavel.ucw.cz>

On Tue, Jul 09, 2013 at 11:49:06AM +0200, Pavel Machek wrote:
> On Mon 2013-07-08 21:13:21, Greg KH wrote:
> > On Tue, Jul 09, 2013 at 03:26:11AM +0200, Pavel Machek wrote:
> > > Hi!
> > > 
> > > My thinkpad has rather high ping latencies... and perhaps it is due to
> > > PCIE ASPM.
> > 
> > Why would that be the problem?  The odds that the PCIE bus is the issue
> > seems strange to me.
> 
> Aha: I guess that's why the file is not writable:
> 
> pavel@amd:~$ dmesg | grep -i aspm 
> ACPI FADT declares the system doesn't support PCIe ASPM, so disable it
> e1000e 0000:02:00.0: Disabling ASPM L0s L1
> pavel@amd:~$ cat /sys/module/pcie_aspm/parameters/policy
> [default] performance powersave 
> pavel@amd:~$ 
> root@amd:~# echo -n performance >
> /sys/module/pcie_aspm/parameters/policy
> -su: echo: write error: Operation not permitted
> root@amd:~# 
> 
> But:
> 1) it should not list unavailable options

It's a module parameter, you can't control if they are present or not
dynamically.

> 2) operation not permitted seems like wrong error code for
> operation not supported.

Then what should it be?

greg k-h

  parent reply	other threads:[~2013-07-09 16:36 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-07-09  1:26 /sys/module/pcie_aspm/parameters/policy not writable? Pavel Machek
2013-07-09  4:13 ` Greg KH
2013-07-09  9:14   ` Pavel Machek
2013-07-09  9:49   ` Pavel Machek
2013-07-09 10:10     ` Pavel Machek
2013-07-09 16:25       ` Bjorn Helgaas
2013-07-10 13:29         ` Pavel Machek
2013-07-10 19:57           ` Bjorn Helgaas
2013-07-10 22:21             ` Wyborny, Carolyn
2013-07-10 22:57               ` Bjorn Helgaas
2013-07-10 22:57                 ` Bjorn Helgaas
2013-07-11 17:45                 ` Wyborny, Carolyn
2013-07-11 17:45                   ` Wyborny, Carolyn
2013-07-12 11:52                 ` Pavel Machek
2013-07-12 11:52                   ` Pavel Machek
2013-07-12 11:03             ` Pavel Machek
2013-07-12 11:11             ` Pavel Machek
2013-07-19 17:46               ` Bjorn Helgaas
2013-07-24 15:19                 ` Wyborny, Carolyn
2013-07-28 13:51                   ` Pavel Machek
2013-08-01 14:55                     ` Wyborny, Carolyn
2013-08-01 15:55                     ` Wyborny, Carolyn
2013-08-02  0:39                       ` Pavel Machek
2013-08-02 14:58                         ` Wyborny, Carolyn
2013-07-31 23:53                 ` Bjorn Helgaas
2013-08-01 14:57                   ` Wyborny, Carolyn
2013-08-01 19:33                     ` Bjorn Helgaas
2013-08-01 20:00                   ` Pavel Machek
2013-08-01 20:27                     ` Bjorn Helgaas
2013-08-02  1:02                       ` Pavel Machek
2013-08-02  2:13                       ` Pavel Machek
2013-08-02 13:48                         ` Bjorn Helgaas
2013-08-01  6:19             ` Jeff Kirsher
2013-07-09 16:37     ` Greg KH [this message]
2013-07-09 17:15       ` Pavel Machek
2013-07-10  4:24     ` Robert Hancock

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