If a kernel hangs early in the boot process (before the console has
been initialized) then printk is no use because you never see the
output. There is a technique for using the video display to indicate
boot progress so you can localize the problem. Reporting "my kernel
hangs during boot at line
On Fri, 22 Sep 2000, Keith Owens wrote:
> If a kernel hangs early in the boot process (before the console has
> been initialized) then printk is no use because you never see the
> output. There is a technique for using the video display to indicate
> boot progress so you can localize the problem
On Thu, 21 Sep 2000 18:54:33 -0400 (EDT),
Byron Stanoszek <[EMAIL PROTECTED]> wrote:
>On Fri, 22 Sep 2000, Keith Owens wrote:
>> The idea is to write characters direct to the video screen during
>> booting using a macro called VIDEO_CHAR.
>
>Why not just redirect printk() to output a string of ch
Keith Owens writes:
> If a kernel hangs early in the boot process (before the console has
> been initialized) then printk is no use because you never see the
> output. There is a technique for using the video display to indicate
> boot progress so you can localize the problem. Reporting "my kern
On Fri, 22 Sep 2000, Keith Owens wrote:
> On Thu, 21 Sep 2000 18:54:33 -0400 (EDT),
> Byron Stanoszek <[EMAIL PROTECTED]> wrote:
> >On Fri, 22 Sep 2000, Keith Owens wrote:
> >> The idea is to write characters direct to the video screen during
> >> booting using a macro called VIDEO_CHAR.
> >
> >
>Hmm, good idea, but how does this work on, say, non-x86 architectures
>which don't have a VGA text frame buffer, or whose VGA text frame buffer
>is not mapped in, or whose VGA text frame buffer is not initialised.
>
>You will still end up with those "my kernel hangs during boot" messages.
>
>A l
>2.4 and 2.2 PPC have progress() for writing progress messages to the
>screen. They're setup in a per-board very early in the boot so we can see
>what's going on as soon as the MMU is turned on and lets us get around.
>
>Ben, can you just make your changes talk through that? I used to use it
>wi
On Sat, 23 Sep 2000 12:42:13 +0200,
Benjamin Herrenschmidt <[EMAIL PROTECTED]> wrote:
>However, there's still a huge gap between the last progress() message and
>availability of the frame buffer device. The simple console has the
>advantage of outputing existing printk messages. (basically, it's
Keith Owens writes:
> Something I forgot to mention about debugging using screen writes. If
> the problem is caused by incorrect compiler output then even printk can
> fail. Not because the C code is wrong but because the generated
> assembler is wrong. Writing direct to screen memory is as sim
On Sat, 23 Sep 2000 13:02:38 +,
Thorsten Kranzkowski <[EMAIL PROTECTED]> wrote:
>How about the possibility to use architecture specific backends? E.g. my
>little Alpha machine has an 8-bit debugging LED port that would be very suited
>for this.
You can define VIDEO_CHAR() to do whatever mak
On Sat, Sep 23, 2000 at 09:57:38PM +1100, Keith Owens wrote:
> On Sat, 23 Sep 2000 12:42:13 +0200,
> Benjamin Herrenschmidt <[EMAIL PROTECTED]> wrote:
> >However, there's still a huge gap between the last progress() message and
> >availability of the frame buffer device. The simple console has th
Benjamin Herrenschmidt wrote:
>
> >Hmm, good idea, but how does this work on, say, non-x86 architectures
> >which don't have a VGA text frame buffer, or whose VGA text frame buffer
> >is not mapped in, or whose VGA text frame buffer is not initialised.
> >
> >You will still end up with those "my
On Sat, 23 Sep 2000, Russell King wrote:
> Keith Owens writes:
> > Something I forgot to mention about debugging using screen writes. If
> > the problem is caused by incorrect compiler output then even printk can
> > fail. Not because the C code is wrong but because the generated
> > assembler
James Sutherland writes:
> On Sat, 23 Sep 2000, Russell King wrote:
> > And I'll try to make the point a second time that everything does not have
> > a character-based screen to write to.
>
> So what? For platforms which have a nice easy way to stick ASCII on
> screen, use this. For other platfo
On Mon, 25 Sep 2000, Russell King wrote:
> James Sutherland writes:
> > On Sat, 23 Sep 2000, Russell King wrote:
> > > And I'll try to make the point a second time that everything does not have
> > > a character-based screen to write to.
> >
> > So what? For platforms which have a nice easy way
Hi!
> > >However, there's still a huge gap between the last progress() message and
> > >availability of the frame buffer device. The simple console has the
> > >advantage of outputing existing printk messages. (basically, it's a
> > >console using prom_printf).
> >
> > Something I forgot to ment
> If a kernel hangs early in the boot process (before the console has
> been initialized) then printk is no use because you never see the
> output. There is a technique for using the video display to indicate
> boot progress so you can localize the problem. Reporting "my kernel
> hangs during bo
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