From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from sipsolutions.net (crystal.sipsolutions.net [195.210.38.204]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTP id 4289CDDE41 for ; Mon, 5 Feb 2007 00:43:44 +1100 (EST) Subject: Re: powerbook/radeon PM problem From: Johannes Berg To: Benjamin Herrenschmidt In-Reply-To: <1170564480.2620.30.camel@localhost.localdomain> References: <1170357083.4036.5.camel@johannes.berg> <1170564480.2620.30.camel@localhost.localdomain> Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="=-/Um13jmLM2bEYF/nmd1R" Date: Sun, 04 Feb 2007 14:42:50 +0100 Message-Id: <1170596570.23273.8.camel@johannes.berg> Mime-Version: 1.0 Cc: linuxppc-dev@ozlabs.org, Paul Mackerras List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , --=-/Um13jmLM2bEYF/nmd1R Content-Type: text/plain Content-Transfer-Encoding: quoted-printable On Sun, 2007-02-04 at 15:47 +1100, Benjamin Herrenschmidt wrote: > Yeah well, it's -supposed- to be taken by the resume function, but the > early resume path is a hack that runs -really- early (so you get a > screen back for debugging). I should find a way to silence those stupid > warnings... Yes, I agree that the semaphore that the comment talks about won't ever be taken anyway. The warning actually comes from the notifier chain that is used there, of course. > > I'm totally unsure what the correct fix for this is. >=20 > None other than removing the early wakeup hack :-( Actually, looking at the code again... fb_notifier_list is a blocking notifier list. This could be converted to a raw one without any locking, and we could require that callers of fb_register_client, fb_unregister_client and fb_notifier_call_chain hold the console semaphore while calling. Then, some callers in drivers/video/fbmem.c would need to be updated, but since fb_set_suspend already requires the semaphore to be held it wouldn't acquire it again, of course. We'd still abuse fb_set_suspend here by calling it without the semaphore held, but we know that nobody else can hold it at that time so that'd be ok. Just a thought. johannes --=-/Um13jmLM2bEYF/nmd1R Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Comment: Johannes Berg (powerbook) iD8DBQBFxeLZ/ETPhpq3jKURAufJAJ0Sx11Ozt/auEqBlIc/UHapFoVoEwCghUi2 kh8eOLte8eVc/u0ophQ9uIQ= =1how -----END PGP SIGNATURE----- --=-/Um13jmLM2bEYF/nmd1R--