1 |
> On Thu, Jun 25, 2020 at 2:55 AM Robin Atwood <robin@×××××.org> wrote: |
2 |
> > |
3 |
> > On Wed, 24 Jun 2020 13:31:30 -0400 |
4 |
> > tedheadster <tedheadster@×××××.com> wrote: |
5 |
> > |
6 |
> > > Robin, |
7 |
> > > are you comfortable just going with a bare-bones console and build a |
8 |
> > > new kernel where you _disable_ CONFIG_FB? That might do it. |
9 |
> > > |
10 |
> > > Alternately, you can hook up a serial cable to another computer and |
11 |
> > > set "console=ttyS0,115200n8". |
12 |
> > |
13 |
> > I will try that, if it works it will at least give me a chance to look |
14 |
> > at the error messages. |
15 |
> > |
16 |
> > I don't think I have any serial cables! |
17 |
> > |
18 |
> |
19 |
|
20 |
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. |
21 |
|
22 |
Most motherboards used to have potentially unpopulated serial port headers on them. Those seen to be disappearing. |
23 |
|
24 |
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. |
25 |
|
26 |
You do need to either make or buy the special A to A cable. |