From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bengt Richter Subject: bug#40538: installer: Support uvesafb to install on machines without KMS. Date: Sun, 12 Apr 2020 19:48:19 +0200 Message-ID: <20200412174819.GA10140@LionPure> References: <20200410125447.smn6xhcixe7hpday@pelzflorian.localdomain> <87tv1rv21e.fsf@gnu.org> <20200411184346.c3cgop7egcjyqzwf@pelzflorian.localdomain> <874ktpspr5.fsf@gnu.org> <20200412090257.jxljqbkwfhn7afnr@pelzflorian.localdomain> <20200412112400.x4qufeztdnkmzqhx@pelzflorian.localdomain> <874ktooj3v.fsf@gmail.com> <20200412153052.ewxdd6m4f6yar2jw@pelzflorian.localdomain> Reply-To: Bengt Richter Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Return-path: Received: from eggs.gnu.org ([2001:470:142:3::10]:51146) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jNgj9-0008LL-BZ for bug-guix@gnu.org; Sun, 12 Apr 2020 13:49:04 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1jNgj8-0004pr-3w for bug-guix@gnu.org; Sun, 12 Apr 2020 13:49:03 -0400 Received: from debbugs.gnu.org ([209.51.188.43]:47263) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1jNgj8-0004pl-0G for bug-guix@gnu.org; Sun, 12 Apr 2020 13:49:02 -0400 Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1jNgj8-0006sz-0G for bug-guix@gnu.org; Sun, 12 Apr 2020 13:49:02 -0400 Sender: "Debbugs-submit" Resent-Message-ID: Content-Disposition: inline In-Reply-To: <20200412153052.ewxdd6m4f6yar2jw@pelzflorian.localdomain> List-Id: Bug reports for GNU Guix List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: bug-guix-bounces+gcggb-bug-guix=m.gmane-mx.org@gnu.org Sender: "bug-Guix" To: "pelzflorian (Florian Pelz)" Cc: 40538@debbugs.gnu.org Hi Florian, On +2020-04-12 17:30:52 +0200, pelzflorian (Florian Pelz) wrote: > On Sun, Apr 12, 2020 at 04:48:36PM +0200, Mathieu Othacehe wrote: > > Thanks for your patch. I tried briefly 1.1.0-rc2 on some hardware of > > mine. On three somehow recent laptops, everything still works fine but > > v86d segfaults without giving much information. > > > > The 'dmesg' output looks like: > > > > --8<---------------cut here---------------start------------->8--- > > v86d[371]: segfault at xxxxx. > > uvesafb: Getting VBE info block failed (eax=0x4f00, err=1) > > uvesafb: vbe_init() failed with -22 > > uvesafb: probe of uvesafb.0 failed with error -22 > > --8<---------------cut here---------------end--------------->8--- > > > > Even though I do not remember a segfault, I believe these errors come > when another driver has already reserved the memory that uvesafb > wants. If the other driver already works fine and that is the only > error, maybe we can just ignore the uvesafb error. > > Could it be segfaulting trying to access a missing v86d ? (if so maybe you could detect its absence before it segfaults and issue a hint?) Looking at https://www.kernel.org/doc/html/latest/fb/uvesafb.html I see (hand-wrapped, and boxing what I thought might be extra interesting): --8<---------------cut here---------------start------------->8--- Unlike other drivers, uvesafb makes use of a userspace helper called v86d. v86d is used to run the x86 Video BIOS code in a simulated and controlled environment. This allows uvesafb to function on arches other than x86. Check the v86d documentation for a list of currently supported arches. v86d source code can be downloaded from the following website: https://github.com/mjanusz/v86d Please refer to the v86d documentation for detailed configuration and installation instructions. ┌───────────────────────────────────────────────────────────────┐ │ Note that the v86d userspace helper has to be available │ │ at all times in order for uvesafb to work properly. │ │ If you want to use uvesafb during early boot, │ │ you will have to include v86d into an initramfs image, │ │ and either compile it into the kernel or use it as an initrd. │ └───────────────────────────────────────────────────────────────┘ --8<---------------cut here---------------end--------------->8--- Also there are various options for compiling in vs modprobe vs kernel params etc mentioned in https://www.kernel.org/doc/html/latest/fb/uvesafb.html so I imagine v86d could be missing for various reasons in a particular run-time context? > > > On a really old Intel machine, I have a complete black screen on all TTY > > but that was maybe the case on older Guix System revisions and I would > > need to do more investigations. > > > > Mathieu > > Please try adding nomodeset to the kernel parameters. I hope this > makes the Intel machine work fine. > > Thank you for your feedback and all your work! > > Regards, > Florian > -- Regards, Bengt Richter