linux-kernel - RE: [PATCH] usb: musb: fix context save over suspend.

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:	Wed, 23 Jan 2013 11:15:26 +0000
From:	"Bilovol, Ruslan" <ruslan.bilovol@...com>
To:	Igor Grinberg <grinberg@...pulab.co.il>, NeilBrown <neilb@...e.de>
CC:	"Balbi, Felipe" <balbi@...com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	"linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-omap@...r.kernel.org" <linux-omap@...r.kernel.org>,
	Kevin Hilman <khilman@...prootsystems.com>
Subject: RE: [PATCH] usb: musb: fix context save over suspend.

Hi,

I faced the same issue on OMAP4 and made similar fix a week ago: http://review.omapzoom.org/31700 but in this patch I also check is the MUSB is already suspended (so the context is already saved) in .suspend callback so reading/writing to MUSB register is more safe.
It is almost same solution as we had a long time ago.

--
Best regards,
Ruslan Bilovol

________________________________________
From: linux-usb-owner@...r.kernel.org [linux-usb-owner@...r.kernel.org] on behalf of Igor Grinberg [grinberg@...pulab.co.il]
Sent: Tuesday, January 22, 2013 11:12 AM
To: NeilBrown
Cc: Balbi, Felipe; Greg Kroah-Hartman; linux-usb@...r.kernel.org; linux-kernel@...r.kernel.org; linux-omap@...r.kernel.org; Kevin Hilman
Subject: Re: [PATCH] usb: musb: fix context save over suspend.

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

It looks like Kevin has a new address:
Kevin Hilman <khilman@...prootsystems.com>

On 01/21/13 23:38, NeilBrown wrote:
> On Mon, 21 Jan 2013 13:38:59 +0200 Igor Grinberg <grinberg@...pulab.co.il>
> wrote:
>
>> -----BEGIN PGP SIGNED MESSAGE-----
>> Hash: SHA1
>
>> Hi Neil,
>
>> On 01/21/13 11:28, NeilBrown wrote:
>>>
>>>
>>> The standard suspend sequence involves runtime_resuming
>>> devices before suspending the system.
>>> So just saving context in runtime_suspend and restoring it
>>> in runtime resume isn't enough.  We  must also save in "suspend"
>>> and restore in "resume".
>>>
>>> Without this patch, and OMAP3 system with off_mode enabled will find
>>> the musb port non-functional after suspend/resume.  With the patch it
>>> works perfectly.
>
>> Hmmm... Some time ago, this has been removed in
>> 5d193ce8 (usb: musb: PM: fix context save/restore in suspend/resume path)
>
>> Am I missing something? Or things changed and now this patch is correct?
>
> Hi Igor,
>  thanks for alerting me to that patch .... does anyone else get the feeling
>  that power management to too complex to be understood by a mere human?
>
>  That commit (5d193ce8) suggests that the musb-hdrc device is an
>  'omap_device', or maybe has a PM domain set to something else.
>  However it isn't/doesn't.  dev->pm_domain is NULL.  So no PM domain layer
>  will ever call the musb_core musb_runtime_suspend/resume.
>
>  The parent device - musb-omap2430 - is an omap device, does have pm_domain
>  set, and does have its omap2430_runtime_suspend/resume called for system
>  suspend and so the context for that device is saved and restored.
>  However that doesn't help the context for musb-hdrc.
>
>  Whether musb ever was an omap_device is beyond my archaeological skills to
>  determine.
>
>  Kevin:  Was musb-hdrc ever a device with a pm_domain? or was it only ever
>      the various possible parents that had domains?
>      Are you able to defend your earlier patch in today's kernel?  It
>      certainly causes my device not to work properly.
>
> Thanks,
> NeilBrown
>
>
>
>
>>>
>>> Signed-off-by: NeilBrown <neilb@...e.de>
>>>
>>> diff --git a/drivers/usb/musb/musb_core.c b/drivers/usb/musb/musb_core.c
>>> index fd34867..b6ccc02 100644
>>> --- a/drivers/usb/musb/musb_core.c
>>> +++ b/drivers/usb/musb/musb_core.c
>>> @@ -2225,6 +2225,7 @@ static int musb_suspend(struct device *dev)
>>>     }
>>>
>>>     spin_unlock_irqrestore(&musb->lock, flags);
>>> +   musb_save_context(musb);
>>>     return 0;
>>>  }
>>>
>>> @@ -2234,6 +2235,8 @@ static int musb_resume_noirq(struct device *dev)
>>>      * unless for some reason the whole soc powered down or the USB
>>>      * module got reset through the PSC (vs just being disabled).
>>>      */
>>> +   struct musb     *musb = dev_to_musb(dev);
>>> +   musb_restore_context(musb);
>>>     return 0;
>>>  }
>>>
>
>> - --
>> Regards,
>> Igor.
>>


- --
Regards,
Igor.
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2.0.17 (GNU/Linux)
Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/

iQIcBAEBAgAGBQJQ/lgWAAoJEBDE8YO64EfacIAP/3nyXjs8QQpcD6RcNuRSLp3O
veKU2grzsUOL/Eu/8TQMM7WDz5n8YlycQ6/THNGGYojjOlEimDC02wbsI4gc5j41
QC1/XGf62Nlxv6CzORzkGkUoKXtVWzgMYKddWKPEwsXMKPun/LH4ZGDp+7Rkfcmu
U0k7LM1Pv487iG9pF3Bq5BPYeMxyxyFJC0PiQEK1ZE65RKWbCvInibc7p1bvZ+XX
JQxf8Qx1p/kBhqWc6LLpcHT5Z3B/F+3rxEhvf8lSu5fdRPHFffcmuX7bIbC/GlTe
e6mODA114mtn5YbaKCmnYExvJcpz4Nziy+8fGLJ56aAyeKI1wsOJzhWDpSKwQiIF
CVtYulk5iIfaeUA4sAzvRqEu7dJuaVgm6mEeGHQjebPastYhK7vHjiEOJJ2+LQrs
698A9wMLckp4AQ75HiwXRgi5N0W528gD8piNoIA9Sh1LwyytIa5Wg7uYw14UjtLJ
QIerm0v6Ay+8FbVfmpm9k0v3HkYfv0ZVTSdtIXVAE30+WKIBTn0yszxWYo6JZtvj
p0NEFUNVuR3C9k/xyzkcqwJh8Q6DrleWJeHWL59xgWWKzfeDKjU/DMOuWmuVEkTO
aRdAlW32VDtUeWlWz3Jz3IOWZRJQKCW2o97n/MDyxwMoRiMWcHxYw6jti6se9S7a
IGZeEMCcf39fnH5o7i2q
=nwGe
-----END PGP SIGNATURE-----
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/