Date: Fri, 20 Apr 2018 17:43:05 -0700 From: Mark Millard <marklmi26-fbsd@yahoo.com> To: Jukka Ukkonen <jau789@gmail.com> Cc: Justin Hibbits <jrh29@alumni.cwru.edu>, FreeBSD PowerPC ML <freebsd-ppc@freebsd.org> Subject: Re: 11.1 release CD image panics very early during boot on ppc. Message-ID: <B750FF47-F65D-49FE-A2AD-A2935209294B@yahoo.com> In-Reply-To: <A0F75C7D-8785-4B37-8A5E-AC0327AE852F@gmail.com> References: <FBADE872-3319-4DE9-9E3C-797DE0CAEED0@gmail.com> <CAHSQbTBysTnBAxm-_PN1APug4iTgUFu160U7Aj0v-GSXhBTv4g@mail.gmail.com> <A0F75C7D-8785-4B37-8A5E-AC0327AE852F@gmail.com>
next in thread | previous in thread | raw e-mail | index | archive | help
On 2018-Apr-20, at 10:23 AM, Jukka Ukkonen <jau789@gmail.com> wrote: > So, I tried setting debug.debugger_on_panic=3D1 and =E2=80=9Dboot = -v=E2=80=9D. > The first time I tried the ofw did not see the full-HD display > which was connected to another system via a KVM switch at > that time. I only got the KVM switched to the correct system > only when I had got the booting stopped at the ofw prompt. > So, the early boot assumed a very traditional 80 columns by > 25 to 30 lines display with a large font. Surprisingly the 11.1 CD > booted just fine. Obviously I wanted to double check and rebooted > the system. This time the display was connected via the KVM > switch to the system right from the start. The ofw obviously figured > out the true full-HD resolution and used a tiny font. When the kernel=20= > got control of the system it selected a bit larger font, showed some > of the autoconfig messages, and went down hard no matter whether > I set the debug.debugger_on_panic=3D1 or not. > This raises the obvious assumption that there must be something > going awry with how vt and ofw communicate and how they try to > control the display. Supposedly this could lead to mismanagement > of a large chunk of memory such that even the debugger is left > totally powerless when the crash happens. Because vt is new to 11.1 > and the properly booting 10.4 uses sc, memory corruption seems > like a plausible explanation to the mysterious crash. >=20 > I hope this helps. >=20 > --jau It has been a long time since I've booted an old PowerMac with vt on my larger displays. I actually build a kernel with both vt and sc in it (no PS3 support) and normally boot sc. My historical reason for avoiding vt was the early stages having a fixed sized memory area tied to what was to be displayed and it going out of bounds of that area and trashing things when I had a large enough display attached. But it has been a very long time since I've done such experiments in this area. So take this note as only suggestive. As I remember, the display types that had the problem were 2560x1440 or something like that. vt would boot fine for smaller displays that I used, such as 1920x1200, as I remember. Looking in the list history (10.x time frames): = https://lists.freebsd.org/pipermail/freebsd-ppc/2014-September/007260.html= = https://lists.freebsd.org/pipermail/freebsd-ppc/2014-September/007263.html= It mattered for GeForce 7800 GT vs. Radeon X1950 for the 2560x1440 behavior. As I remember, the maximum screen size involved in the kernel was changed as Nathan indicates, but still to some fixed figures for the early code. Likely still a problem for a sufficiently large display. (Beyond what I have access to now.) (The xf86-video-scfb suggestion did not work for the X1950. I stopped using X on the old PowerMac long ago.) >> On 17 Apr 2018, at 18.11, Justin Hibbits <jrh29@alumni.cwru.edu> = wrote: >>=20 >> Hi, >>=20 >>> On Sun, Apr 15, 2018 at 2:10 AM, Jukka Ukkonen <jau789@gmail.com> = wrote: >>>=20 >>> I had a bit of an accident with my old PowerMac G4 which had been >>> running FreeBSD-10.4. To fix the mess I had to boot the system from >>> a CD image. So, I decided to try 11.1 while at it. To my = astonishment >>> and disappointment the 11.1 images (both CD and DVD) paniced >>> very early on during the boot. The messages flashed past the screen >>> so quickly that I cannot be really sure about anything, but it kind = of >>> seemed like the issue might be yet another installment of the SPRG >>> related problems (in ofw_machdep.c) which have been troubling >>> ppc64 systems before. >>> The 10.4 CD image boots just fine on ppc. >>>=20 >>> --jau >>=20 >> Can you try booting with 'boot -v' and also setting at the loader >> debug.debugger_on_panic=3D1? I think it's set to 0 on release ISOs, = so >> this should let you get a screen capture. >>=20 >> - Justin =3D=3D=3D Mark Millard marklmi at yahoo.com ( dsl-only.net went away in early 2018-Mar)
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?B750FF47-F65D-49FE-A2AD-A2935209294B>