From mboxrd@z Thu Jan 1 00:00:00 1970 From: Martin Waitz Subject: Re: [Linux-fbdev-devel] Generic VESA framebuffer driver and Video card BOOT? Date: Mon, 18 Oct 2004 13:39:29 +0200 Sender: linux-kernel-owner@vger.kernel.org Message-ID: <20041018113929.GB3618@admingilde.org> References: <416E6ADC.3007.294DF20D@localhost> <87d5zkqj8h.fsf@bytesex.org> <87y8i8p1jq.fsf@bytesex.org> <20041017120728.GC10532@admingilde.org> <20041018083632.GE3065@bytesex> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="7ZAtKRhVyVSsbBD2" Return-path: Content-Disposition: inline In-Reply-To: <20041018083632.GE3065@bytesex> List-Id: Cc: linux-fbdev-devel@lists.sourceforge.net, Linux Kernel Development , penguinppc-team@lists.penguinppc.org --7ZAtKRhVyVSsbBD2 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable hi :) On Mon, Oct 18, 2004 at 10:36:32AM +0200, Gerd Knorr wrote: > On Sun, Oct 17, 2004 at 02:07:28PM +0200, Martin Waitz wrote: > > On Fri, Oct 15, 2004 at 03:13:13PM +0200, Gerd Knorr wrote: > > > You have a application running which uses the framebuffer device, then > > > suspend with that app running. You'll have to restore the state of > > > the device _before_ restarting all the userspace proccesses, otherwise > > > the app will not be very happy. > >=20 > > As long as the app only interfaces with the framebuffer device and not > > directly with the hardware it won't notice. >=20 > Well, mmap("/dev/fb") will just map the gfx cards memory into > the applications address space, so they _will_ interface with > the hardware. but still through a driver which can take care of this access. > > The apps data will simply not show up on the screen until the > > usermode helper finishes. >=20 > Whenever writing to the gfx memory before finishing the initialization > is harmless or not probably depends on the hardware, I'd better not > count on it ... when the application tries to access the framebuffer memory then the driver is asked to map the corresponding page. If the hardware does not cope with framebuffer access while it is not correctly initialized, then the driver can defer those mappings until the userspace helper is run. --=20 Martin Waitz --7ZAtKRhVyVSsbBD2 Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.1 (GNU/Linux) iD8DBQFBc6twj/Eaxd/oD7IRAoboAJ9KreNPAGUNdcMAOn1yQiEAKqKeggCdEP9g Qb0rzXaKA2dW8M8EnE6UfrY= =EH4+ -----END PGP SIGNATURE----- --7ZAtKRhVyVSsbBD2--