Re: [Linux-fbdev-devel] ruby on pm3/i386

[Sven L. <lu...@la...>]

On Wed, Sep 05, 2001 at 05:51:53PM +0200, Romain Dolbeau wrote:
> James Simmons wrote:
> 
> > That sounds like a bug in the check_var function. When I get the chance I
> > will go threw the code.
> 
> Dunno if it was the bug, but my ugly code had an ugly bug that
> needed an ugly fix (commited). if set_par was ever called prior
> to that check_var, then it was the bug (the pointer
> to the hardware-specific state got erased and never restored...)

More checking gave the following :

1) the bug number one seem to be because some of the __fb_try_mode call are
done with a NULL info->fbops pointer. I don't understand why that is so, but
anyway naturally it will hang when trying to acceess
info->fbops->fb_check_var.

When returning 0 when info->fpops is null, i managed to get a bit further, but
could not see more than the last lines of the debug because of the oops. Is
there a way to access the log in this case, apart from a serial console, which
i don't have ? On amiga, it was possible to get access to a log saved in
memory with the amigaOS version of the dmesg program, i suppose this is not
possible on i386,at least not with lilo/grub ? mmm, maybe grub can look at the
memory at some location, and i can read it there.

Anyway, i returned 0, and it followed a bit, but again hang as follows :

kernel_thread
init
pm3fb_open
pm3fb_detect
pm3fb_common_init
fb_copy_cmap.
  -> here it hangs in the first line, where we access tyo->start and from->
  start to calculate tooff, to and from don't seem to be NULL though, which
  seems strange to me because nothing more happens there, but then maybe i
  botched soem of the printks i used.

Also, Romain, when enabling MASTER_DEBUG=3, i had to do some file editing,
because there were various problems which hindered the compilation, but the
last message i got where :

pm3fb_realsetup : setting mode for board #0. (but i think this was still
without the workaround to bug #1, don't remember exactly).

Hope this helps somewhat, please keep me informed on further evolution, and i
will hapilly test them.

BTW, is it possible to build a modular fb stuff + pm3fb, so as to shorten
build and test time, and maybe get more informative log messages, or will this
not work/not show the right info ?

Friendly,

Sven Luther