From: Marcel Holtmann <marcel@holtmann.org>
To: Alan Stern <stern@rowland.harvard.edu>
Cc: Takashi Iwai <tiwai@suse.de>, Laura Abbott <labbott@redhat.com>,
Laura Abbott <labbott@fedoraproject.org>,
"Gustavo F. Padovan" <gustavo@padovan.org>,
Johan Hedberg <johan.hedberg@gmail.com>,
"David S. Miller" <davem@davemloft.net>,
"bluez mailin list (linux-bluetooth@vger.kernel.org)"
<linux-bluetooth@vger.kernel.org>,
netdev <netdev@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Ming Lei <ming.lei@canonical.com>,
"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
linux-usb@vger.kernel.org
Subject: Re: [RESEND][PATCH] Bluetooth: Make request workqueue freezable
Date: Tue, 19 May 2015 17:22:26 +0200 [thread overview]
Message-ID: <E00D9D09-50A7-46C8-B141-9338F85B0020@holtmann.org> (raw)
In-Reply-To: <Pine.LNX.4.44L0.1505191017460.1453-100000@iolanthe.rowland.org>
Hi Alan,
>>>> I am not convinced. Now we are hacking the Bluetooth core layer
>>>> (which has nothing to do with the drivers suspend/resume or
>>>> probe) to do something different so that we do not see this
>>>> warning.
>>>>
>>>> I can not do anything about the platform in question choosing a
>>>> unplug/replug for suspend/resume instead of having a proper USB
>>>> suspend and resume handling. That is pretty much out of our
>>>> control.
>
> Actually one can do something about this. I mean, one _can_ implement
> proper USB suspend and resume handling in the Bluetooth driver. At
> this point the details aren't clear to me, but perhaps if the driver in
> question had a reset_resume callback then it might work better.
the btusb.ko driver has suspend/resume support. Are you saying we also need reset_resume support?
>>>> I would rather have the USB subsystem delay the probe()
>>>> callback if we tell it to.
>
> This is possible. I am not sure it would be the right thing to do,
> though. What happens if the probe routine gets called early on during
> the boot-up procedure, before userspace is up and running? The same
> thing should happen here.
For modules this will be hard. Since you need userspace before being able to load the modules. If built-in code, then in theory this might be possible. Depending on the order of the init sections.
>>>> Of just have request_firmware()
>>>> actually sleep until userspace is ready. Seriously, why is
>>>> request_firmware not just sleeping for us.
>
> It won't work. The request_firmware call is part of the probe
> sequence, which in turn is part of the resume sequence. Userspace
> doesn't start running again until the resume sequence is finished. If
> request_firmware waited for userspace, it would hang.
Then I really have no idea on how to solve this unless we silence the warning from request_firmware. From a driver perspective we go back trough probe(). So the driver has to treat this as a new device.
Regards
Marcel
next prev parent reply other threads:[~2015-05-19 15:22 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-12 0:52 [RESEND][PATCH] Bluetooth: Make request workqueue freezable Laura Abbott
2015-05-12 1:07 ` Marcel Holtmann
2015-05-12 1:46 ` Laura Abbott
2015-05-12 15:14 ` Marcel Holtmann
2015-05-13 1:18 ` Laura Abbott
2015-05-19 9:46 ` Takashi Iwai
2015-05-19 14:26 ` Alan Stern
2015-05-19 14:52 ` Oliver Neukum
2015-05-19 15:22 ` Marcel Holtmann [this message]
2015-05-19 17:17 ` Alan Stern
2015-05-19 17:13 ` Takashi Iwai
2015-05-19 17:42 ` Oliver Neukum
2015-05-20 6:29 ` Takashi Iwai
2015-05-20 8:40 ` Oliver Neukum
2015-05-20 9:46 ` Marcel Holtmann
2015-05-20 12:44 ` Takashi Iwai
2015-05-20 23:42 ` Laura Abbott
2015-05-21 4:21 ` Takashi Iwai
2015-05-21 12:07 ` Marcel Holtmann
2015-05-21 12:36 ` Takashi Iwai
2015-05-21 14:18 ` Alan Stern
2015-05-21 14:39 ` Marcel Holtmann
2015-05-21 15:26 ` Alan Stern
2015-05-21 15:35 ` Takashi Iwai
2015-05-21 17:27 ` Arend van Spriel
2015-05-21 17:32 ` Takashi Iwai
2015-05-21 20:46 ` Arend van Spriel
2015-05-22 11:30 ` Oliver Neukum
2015-05-21 17:37 ` Alan Stern
2015-05-21 18:11 ` Takashi Iwai
2015-05-21 18:17 ` Laura Abbott
2015-05-22 0:21 ` Laura Abbott
2015-05-22 3:13 ` Marcel Holtmann
2015-05-28 0:47 ` Laura Abbott
2015-06-02 1:14 ` [PATCH 1/2] Bluetooth: Add reset_resume function Laura Abbott
2015-06-02 1:28 ` Marcel Holtmann
2015-06-02 14:17 ` Josh Boyer
2015-06-02 15:07 ` Marcel Holtmann
2015-06-02 7:47 ` Oliver Neukum
2015-06-02 1:14 ` [PATCH 2/2] Bluetooth: btusb: " Laura Abbott
2015-06-02 1:32 ` Marcel Holtmann
2015-05-22 7:37 ` [RESEND][PATCH] Bluetooth: Make request workqueue freezable Arend van Spriel
2015-05-22 7:41 ` Arend van Spriel
2015-05-21 15:04 ` Takashi Iwai
2015-05-20 10:02 ` Ming Lei
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