[gentoo-user] Initial console messages garbled [REPOST]
Since as Dale and others have pointed out, I posted my first message on this subject by using an existing message as a template which doesn't work because it gets added to the existing thread. So here goes again. (I have also just noticed some replies that I had missed for the same reason: lesson learned! Rich's response looks very useful.) I posted about this on the Gentoo forums (see [1]) but didn't get any response so I'll try my luck here! The post explains everything but. briefly, normally when I boot a kernel I initially get some messages in a large clunky font, and then the frame-buffer module loads and everything is hi-res and fills the entire monitor. On my new box the first messages are video-static until the frame-buffer takes over. I have an error in a new root partition I have built and need to read those messages! What of all the numerous parameters in various places should I try tweaking? Thanks Robin 1. http://forums.gentoo.org/viewtopic-t-1114668-highlight-.html > From: "Sid Spry" > To: gentoo-user@lists.gentoo.org > Subject: Re: [gentoo-user] Initial console messages garbled > Date: Sun, 28 Jun 2020 11:03:12 -0500 > Reply-to: gentoo-user@lists.gentoo.org > User-Agent: > Cyrus-JMAP/3.3.0-dev0-543-gda70334-fm-20200618.004-gda703345 > X-Mailer: MessagingEngine.com Webmail Interface > > > On Thu, Jun 25, 2020 at 2:55 AM Robin Atwood > > wrote: > > > > > > On Wed, 24 Jun 2020 13:31:30 -0400 > > > tedheadster wrote: > > > > > > > Robin, > > > > are you comfortable just going with a bare-bones console and > > > > build a new kernel where you _disable_ CONFIG_FB? That might do > > > > it. > > > > > > > > Alternately, you can hook up a serial cable to another computer > > > > and set "console=ttyS0,115200n8". > > > > > > I will try that, if it works it will at least give me a chance to > > > look at the error messages. > > > > > > I don't think I have any serial cables! > > > > > > > Well, you may need to buy a cable one way or another if your issue is > very early in the boot process, typically qualified as "before the > console comes up." Netconsole may help you though. > > Most motherboards used to have potentially unpopulated serial port > headers on them. Those seen to be disappearing. > > The replacement is > https://www.kernel.org/doc/html/v5.4/driver-api/usb/usb3-debug-port.html. > Most (all?) desktop xHCI controllers support a device mode that is > essentially a very high speed CBC ACM serial port. This is especially > useful for debugging laptops. > > You do need to either make or buy the special A to A cable. > From: Rich Freeman > To: gentoo-user@lists.gentoo.org > Subject: Re: [gentoo-user] Initial console messages garbled > Date: Sun, 28 Jun 2020 10:51:26 -0400 > Reply-to: gentoo-user@lists.gentoo.org > > On Thu, Jun 25, 2020 at 2:55 AM Robin Atwood wrote: > > > > On Wed, 24 Jun 2020 13:31:30 -0400 > > tedheadster wrote: > > > > > Robin, > > > are you comfortable just going with a bare-bones console and > > > build a new kernel where you _disable_ CONFIG_FB? That might do > > > it. > > > > > > Alternately, you can hook up a serial cable to another computer > > > and set "console=ttyS0,115200n8". > > > > I will try that, if it works it will at least give me a chance to > > look at the error messages. > > > > I don't think I have any serial cables! > > > > While serial consoles are one solution, I'd take a look at network > consoles. They're FAR easier to manage on commodity hardware. All > you really need is another host on the network that can run netcat. > > I stick this in my /etc/grub/default - or otherwise get it onto the > command line in the bootloader: > netconsole=@/,@192.168.1.1 > > That tells the kernel to send all console output over UDP to > 192.168.1.1:. If you have multiple interfaces/etc you might need > to expand that command line a bit. I have no idea how it comes up > with the sending IP - if you care about that you can specify it. I'm > guessing it doesn't run DHCP - but this is just plain UDP so it is > one-way and there is no need for acks to get back to the sender. > > On the destination host I run: > nc -u -l -p > > (nc is provided by the netcat package - a very basic tool that should > be available everywhere - probably on non-linux operating systems > also) > > Start up the reception part before you try booting the host you're > troubleshooting, because it is just going to send packets
Re: [gentoo-user] Initial console messages garbled
Robin Atwood wrote: > > Given the almost total lack of response to my post, I guess I am stuck > with this problem. > > Thanks > Robin The likely reason you are not getting many responses, you replied to a message in another thread and only changed the subject line. I don't know anything about suspend to ram so I been marking this thread as read as new replies appeared. When I clicked on the folder for -user mailing list, then I noticed the change in the subject since the thread was expanded. I think this is the first message I saw on this subtopic. I suspect, others on this list are doing the same thing as me. What I would suggest is starting a new thread about your topic. That way people will be more likely to see your topic instead of the topic that someone else started that is not related to this. Just a thought. It may not help but you won't know until you try. Dale :-) :-)
Re: [gentoo-user] Initial console messages garbled
> On Thu, Jun 25, 2020 at 2:55 AM Robin Atwood wrote: > > > > On Wed, 24 Jun 2020 13:31:30 -0400 > > tedheadster wrote: > > > > > Robin, > > > are you comfortable just going with a bare-bones console and build a > > > new kernel where you _disable_ CONFIG_FB? That might do it. > > > > > > Alternately, you can hook up a serial cable to another computer and > > > set "console=ttyS0,115200n8". > > > > I will try that, if it works it will at least give me a chance to look > > at the error messages. > > > > I don't think I have any serial cables! > > > Well, you may need to buy a cable one way or another if your issue is very early in the boot process, typically qualified as "before the console comes up." Netconsole may help you though. Most motherboards used to have potentially unpopulated serial port headers on them. Those seen to be disappearing. The replacement is https://www.kernel.org/doc/html/v5.4/driver-api/usb/usb3-debug-port.html. Most (all?) desktop xHCI controllers support a device mode that is essentially a very high speed CBC ACM serial port. This is especially useful for debugging laptops. You do need to either make or buy the special A to A cable.
Re: [gentoo-user] Initial console messages garbled
On Thu, Jun 25, 2020 at 2:55 AM Robin Atwood wrote: > > On Wed, 24 Jun 2020 13:31:30 -0400 > tedheadster wrote: > > > Robin, > > are you comfortable just going with a bare-bones console and build a > > new kernel where you _disable_ CONFIG_FB? That might do it. > > > > Alternately, you can hook up a serial cable to another computer and > > set "console=ttyS0,115200n8". > > I will try that, if it works it will at least give me a chance to look > at the error messages. > > I don't think I have any serial cables! > While serial consoles are one solution, I'd take a look at network consoles. They're FAR easier to manage on commodity hardware. All you really need is another host on the network that can run netcat. I stick this in my /etc/grub/default - or otherwise get it onto the command line in the bootloader: netconsole=@/,@192.168.1.1 That tells the kernel to send all console output over UDP to 192.168.1.1:. If you have multiple interfaces/etc you might need to expand that command line a bit. I have no idea how it comes up with the sending IP - if you care about that you can specify it. I'm guessing it doesn't run DHCP - but this is just plain UDP so it is one-way and there is no need for acks to get back to the sender. On the destination host I run: nc -u -l -p (nc is provided by the netcat package - a very basic tool that should be available everywhere - probably on non-linux operating systems also) Start up the reception part before you try booting the host you're troubleshooting, because it is just going to send packets blind into the ether and if nothing is listening they're gone. Obviously netconsole is a very simple implementation so that it can run during early boot. It is very good for capturing panics/etc. I don't know how it compares with serial console in terms of how early it starts. I think it does capture stuff very early in boot though - both systems require a degree of hardware initialization before they can work, but both are also very simple. This does need to be enabled in the kernel. You can also enable this on a running kernel but of course that does no good for issues during boot. Full docs are at: https://www.kernel.org/doc/Documentation/networking/netconsole.txt -- Rich
Re: [gentoo-user] Initial console messages garbled
On Thu, 25 Jun 2020 13:55:18 +0700 > > Robin, > > are you comfortable just going with a bare-bones console and build > > a new kernel where you _disable_ CONFIG_FB? That might do it. > > > > Alternately, you can hook up a serial cable to another computer and > > set "console=ttyS0,115200n8". > > I will try that, if it works it will at least give me a chance to look > at the error messages. I couldn't disable CONFIG_FB in the kernel, only select "module" or "built-in" mode. I guess there is another parameter which needs disabling. Researching that, I discovered you can disable frame-buffer on the kernel command line. Also, that there might be an option in the BIOS to set but I checked that and found nothing. So I rebooted and used Grub to edit the kernel parameters and set "VGA=NORMAL NOMODESET". This resulted in the usual initial garbage which was not cured by loading the frame-buffer module. So disabling frame-buffer support made things worse, which is rather what I was expecting. :( Given the almost total lack of response to my post, I guess I am stuck with this problem. Thanks Robin --
Re: [gentoo-user] Initial console messages garbled
On Wed, 24 Jun 2020 13:31:30 -0400 tedheadster wrote: > Robin, > are you comfortable just going with a bare-bones console and build a > new kernel where you _disable_ CONFIG_FB? That might do it. > > Alternately, you can hook up a serial cable to another computer and > set "console=ttyS0,115200n8". I will try that, if it works it will at least give me a chance to look at the error messages. I don't think I have any serial cables! Thanks Robin --
Re: [gentoo-user] Initial console messages garbled
On Wed, 24 Jun 2020 12:54:32 -0400 Jack wrote: > I can't answer your question, but I can suggest that you start a new > thread with a new message, not replying to an old message, even if > you do change the subject. Many email readers thread discussions > using internal message headers, not just subject, so it increases the > chance your message may not be seen by someone who can answer. > > Jack Thanks for pointing that out, it was the easiest way to post! Robin --
Re: [gentoo-user] Initial console messages garbled
Robin, are you comfortable just going with a bare-bones console and build a new kernel where you _disable_ CONFIG_FB? That might do it. Alternately, you can hook up a serial cable to another computer and set "console=ttyS0,115200n8". - Matthew
Re: [gentoo-user] Initial console messages garbled
On 2020.06.24 12:39, Robin Atwood wrote: I posted about this on the Gentoo forums (see [1]) but didn't get any response so I'll try my luck here! The post explains everything but. briefly, normally when I boot a kernel I initially get some messages in a large clunky font, and then the frame-buffer module loads and everything is hi-res and fills the entire monitor. On my new box the first messages are video-static until the frame-buffer takes over. I have an error in a new root partition I have built and need to read those messages! What of all the numerous parameters in various places should I try tweaking? Thanks Robin 1. http://forums.gentoo.org/viewtopic-t-1114668-highlight-.html I can't answer your question, but I can suggest that you start a new thread with a new message, not replying to an old message, even if you do change the subject. Many email readers thread discussions using internal message headers, not just subject, so it increases the chance your message may not be seen by someone who can answer. Jack
[gentoo-user] Initial console messages garbled
I posted about this on the Gentoo forums (see [1]) but didn't get any response so I'll try my luck here! The post explains everything but. briefly, normally when I boot a kernel I initially get some messages in a large clunky font, and then the frame-buffer module loads and everything is hi-res and fills the entire monitor. On my new box the first messages are video-static until the frame-buffer takes over. I have an error in a new root partition I have built and need to read those messages! What of all the numerous parameters in various places should I try tweaking? Thanks Robin 1. http://forums.gentoo.org/viewtopic-t-1114668-highlight-.html -- -- Robin Atwood. --
