Re: PowerBook G3 Wallstreet Hang Using Debian Kernel

On 10/31/25 5:32 PM, Cedar Maxwell wrote:
> Hi Stan,
> 
> 
> Thanks for the update. I'll try your config and see how it works. My 
> WallStreet is actually 1024x768, 266MHz, 512MiB, just like yours. 

My mistake.

> Although, with no module support, I wonder if it is better just to stick 
> with kernel 6.3, since it appears to work fine? I seem to have no issue 
> running the same latest packages as on my G4, and am frankly unfamiliar 
> with how much of an issue it will be to continue using an outdated kernel.

All of the Debian SID packages should continue to work with kernel 6.3, 
at least for a while. So if you're happy enough with 6.3, it might be 
best to stick with that for now.

> 
> 
> Did you ever end up submitting that bug report on the Linux PPC dev 
> mailing list? I would do it myself, but clearly you have better 
> knowledge of the issue (and I wouldn't want to steal your cred).

I really don't care about cred.

> I saw you posted a report on the Pismo, but if you posted one on the 
> WallStreet too I must've missed it.

I did post a report regarding the Pismo, but that problem (solved by 
Finn; see below) was Open Firmware related and turned out to be 
unrelated to the Wallstreet hang.

For the Wallstreet hang, Finn determined that the issue appears to be 
related to the use of CONFIG_BOOTX_TEXT=y in the config file, though 
it's not clear (yet) whether that's a kernel regression or an issue with 
BootX on Old World PowerMac systems such as the Wallstreet that have 
Open Firmware (the PowerBook 3400c also hangs, BTW).

So I'm looking at whether it makes sense to attempt a kernel bisect. 
I'll send an update if I find anything.

> 
> 
> 
> On 10/28/25 10:43 AM, Stan Johnson wrote:
>> Hi Cedar,
>>
>> I haven't been able to determine a reason for the hang of Debian's 
>> default kernel/initrd combination (6.16.9+deb14-powerpc) on the 
>> PowerPC PowerBook G3 Series laptop (Wallstreet).
>>
>> Finn Thain (cc'ed on this message) found a bug that was causing video 
>> to not work correctly (see "https://lkml.org/lkml/2025/10/9/639"). 
>> Unfortunately, as it turns out, that bug was not related to the Debian 
>> hang.
>>
>> I'm able to reproduce the hang on my Wallstreet (266 MHz, 512 MiB) 
>> using an updated Debian SID and the Debian kernel/initrd. However, the 
>> hang doesn't happen on my PowerBook Lombard or Pismo. As you've 
>> reported, the symptoms are that the screen goes blank and the 
>> backlight stays on, and the system freezes (Linux doesn't boot).
>>
>> And there's no output from the serial port. It's possible that there's 
>> an issue with BootX not being able to handle large initrd.img files 
>> (initrd.img-6.16.9+deb14-powerpc is over 40 MB), but I really have no 
>> idea. I tried adjusting the memory for BootX in Mac OS 9 to 64 MiB, 
>> but the hang persists. I also tried adding sccdbg and initcall_debug 
>> to the kernel command line, as suggested by Finn, but neither 
>> generated any serial output, which suggests (to me) an issue with 
>> BootX. I have not found any combination of BootX options that will 
>> produce serial output.
>>
>> And I haven't been able to test the effect of config file changes to 
>> Debian's kernel because config-6.16.9+deb14-powerpc does not produce 
>> the kernel and modules that Debian distributes (the new vmlinux is 
>> over 200 MB, modules are over 300 MB, bZimage is around 9 MB). I could 
>> start stipping out debugging and other features, but that would make 
>> the kernel quite different. Without being able to reproduce Debian's 
>> kernel, I'm stuck.
>>
>> Using the attached config-6.17.5-pmac, which is a limited config file 
>> that includes only the options that are needed for most PowerPC G3 and 
>> earlier PowerPC PowerBooks, with no module support, everything works 
>> as expected, with both "video=ofonly" (check "No video driver" with no 
>> extra command line options), or the usual 
>> "video=atyfb:vmode:14,cmode:32,mclk:71" for my 1024x768 Wallstreet.
>>
>> For your 800x600 Wallstreet, "video=atyfb:vmode:10,cmode:32" should 
>> work. It should also work to check "No video driver" in BootX with no 
>> extra command line options in BootX.
>>
>> I'm using kernel 6.17.5 from www.kernel.org, but the latest mainline 
>> kernels also work.
>>
>> -Stan
>