From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with archive (Exim 4.43) id 1OVvpe-0004BD-Hn for mharc-grub-devel@gnu.org; Mon, 05 Jul 2010 20:16:14 -0400 Received: from [140.186.70.92] (port=40133 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1OVvpb-0004B5-AN for grub-devel@gnu.org; Mon, 05 Jul 2010 20:16:12 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.69) (envelope-from ) id 1OVvpa-0006kP-4H for grub-devel@gnu.org; Mon, 05 Jul 2010 20:16:11 -0400 Received: from mail-ew0-f41.google.com ([209.85.215.41]:63496) by eggs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1OVvpZ-0006k9-UN for grub-devel@gnu.org; Mon, 05 Jul 2010 20:16:10 -0400 Received: by ewy28 with SMTP id 28so1956647ewy.0 for ; Mon, 05 Jul 2010 17:16:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:message-id:date:from :user-agent:mime-version:to:cc:subject:references:in-reply-to :x-enigmail-version:content-type; bh=ufPVLdFjV0hPjV8b1hasPVkurBAtULwo06WNeUbtXQI=; b=Fx24YEKk1QonYnPo+nwoiWzyv0bjXJEq+lL/NaZahCMethJnVdVmBHhs8GdLGZBOTJ Pzq0o6UTyDwQjSHYXAQSgdUma6qlNCcnb9UqwmYlzNRFJ+lahMMDIUTI+Lq+QUowxp3F zcLsusC1bsZaM1bCx6DO4ikzR9ZbL21z15+fg= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:user-agent:mime-version:to:cc:subject :references:in-reply-to:x-enigmail-version:content-type; b=umso4ixQxRDms7ZC8zd0Xl/uF5ktIjDnX+ZcPG61r9E1Fqqji1RSQVMXLgcbx20caN VfZBfMmtx8duErLBTRcAejbo7UbpI08xCOZc4j4vD9AxANDzrRCjBXhb3ocVge51Cm0G l5BhANCQLM/CAQsNcm3RifvXrrh4Ud0typgVU= Received: by 10.213.27.206 with SMTP id j14mr3134061ebc.28.1278375368934; Mon, 05 Jul 2010 17:16:08 -0700 (PDT) Received: from debian.bg45.phnet ([109.229.191.139]) by mx.google.com with ESMTPS id a48sm40728167eei.13.2010.07.05.17.16.07 (version=TLSv1/SSLv3 cipher=RC4-MD5); Mon, 05 Jul 2010 17:16:08 -0700 (PDT) Message-ID: <4C3275C7.1020209@gmail.com> Date: Tue, 06 Jul 2010 02:16:07 +0200 From: =?UTF-8?B?VmxhZGltaXIgJ8+GLWNvZGVyL3BoY29kZXInIFNlcmJpbmVua28=?= User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.10) Gecko/20100620 Icedove/3.0.5 MIME-Version: 1.0 To: The development of GNU GRUB References: <20100705170023.GF21862@riva.ucam.org> In-Reply-To: <20100705170023.GF21862@riva.ucam.org> X-Enigmail-Version: 1.0.1 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="------------enig68DD592F5FD27BF7CE978CBC" X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6 (newer, 2) Cc: Matthew Garrett , Colin Watson , Andy Whitcroft Subject: Re: [PATCH] Rework vesafb/efifb handling in GRUB X-BeenThere: grub-devel@gnu.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: The development of GNU GRUB List-Id: The development of GNU GRUB List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 06 Jul 2010 00:16:13 -0000 This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig68DD592F5FD27BF7CE978CBC Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On 07/05/2010 07:00 PM, Colin Watson wrote: > I've been looking once again at supporting relatively smooth visual > transitions from GRUB to the kernel, which entails deploying 'set > gfxpayload=3Dkeep' in Ubuntu (I've had it turned off for a while due to= > various reported problems of the black-screen type). I talked with > Matthew Garrett (CCed), a Linux kernel developer friend of mine who > knows about the video subsystem, about what would be involved here. > > Initially I was strongly advocating using efifb for this, since, hey, > GRUB already uses it by default and labels it as > GRUB_VIDEO_LINUX_TYPE_SIMPLE, so it must be the simplest option, right?= > Matthew pointed out that GRUB's current behaviour is actually quite > wrong as far as Linux is concerned. It happens to work with the kernel= > as it is now, because once efifb has been programmed with the > framebuffer base address etc. it just acts as a simple linear > framebuffer. However, in the future, the Linux developers might well > change efifb to support the EFI virtual machine and use EFI for > modesetting (and they'd be entitled to do so given its name!), IMHO it's a plain overkill. efifb main use is to supply the transition until the real KMS driver is loaded or for recovery situations. Implementing anything more than framebuffer writing seems to be work for nothing for me. > and at > this point using efifb on non-EFI systems will break. Matthew said > "It's really a bug that efifb doesn't check efi_enabled before binding"= , > =20 AFAIK EFI doesn't have any useful functions when bootloader is terminated= =2E > so it seems clear to me that GRUB's current code only works by luck. > > =20 > All we actually need is a simple linear framebuffer that we can program= > using the boot screen_info structure and that can support displaying > text quite early in kernel startup (at least to the extent of being abl= e > to show output if the initramfs fails to mount the root filesystem). > vesafb gives us this just as well as efifb does. > > =20 No it doesn't. Passing vesafb we claim that: a) vesa is working b) mode was set by vesa. Both assumptions are plainly wrong when GRUB uses native driver, especially in vbe-free environment. This leads to kernel crash. > The following patch renames GRUB_VIDEO_LINUX_TYPE_SIMPLE back to > something less misleading, and programs vesafb rather than efifb on BIO= S > systems. I'm ok to use another ID if Linux standartises the ID when bootloader claims "at this fb address you have a simple framebuffer with following characteristics, don't even try to use firmware, unload in handover to real driver for the same card" --=20 Regards Vladimir '=CF=86-coder/phcoder' Serbinenko --------------enig68DD592F5FD27BF7CE978CBC Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iF4EAREKAAYFAkwydccACgkQNak7dOguQgnbsAEAkl+M4rlNhNnvtRHOmKZerp0Y VxpFNKFoX+kDdfc7kbMA/jH5AB5gL0EuIwqoGDyTj2lbGM4t6BVzaa1LDNee0Puz =nNDO -----END PGP SIGNATURE----- --------------enig68DD592F5FD27BF7CE978CBC--