Re: kernel panic with new pseudo device

[matthew sporleder <msporleder%gmail.com@localhost>]

On 5/21/09, matthew sporleder <msporleder%gmail.com@localhost> wrote:
> On Thu, May 21, 2009 at 11:00 AM, Quentin Garnier 
> <cube%cubidou.net@localhost> wrote:
>  > On Thu, May 21, 2009 at 09:24:31AM -0400, matthew sporleder wrote:
>  >> Hi, I'm trying to write a pseudo device with an envsys component.  I
>  >> mostly followed http://www.netbsd.org/docs/kernel/pseudo/ and got a
>  >> working device, but now I get a panic when I attempt to do:
>  >> sc->sc_sme = sysmon_envsys_create();
>  >>
>  >> My best guess is that I didn't get any memory allocated for my _softc
>  >> structure, but I'm not really sure how to validate that.
>  >>
>  >> A rough cut of my code is here:
>  >> http://mspo.com/code/screenblankenv.c.txt
>  >>
>  >> Can anyone offer some hints?  I'm a little stuck.
>  >
>  > autoconf(9) can be confusing at times.  And the fact that the example
>  > code is wrong doesn't help.
>  >
>  > If you read http://www.netbsd.org/docs/kernel/pseudo/#functions, you'll
>  > notice that the <pseudo>attach function only takes one argument, which
>  > is an int (the number given in the config file, which defaults to 1).
>  >
>  > There is no softc involved for pseudo-devices (although if you use
>  > defpseudodev to declare it, you get the possibility to make that happen,
>  > but even then there is more work to do;  it doesn't seem to me this is
>  > what you want though).
>  >
>  > So because <pseudo>attach is called with no device context, you have to
>  > do all memory allocations by yourself.  I'll fix the example.
>  >
>
>
>
> Thanks!  I was really suspicious of an allocation problem but I didn't
>  see any other devices doing mallocs so I wasn't that confident.  I'll
>  look forward to seeing the fixed example.  :)
>

I made it past my panic with the following:
struct screenblankenv_softc *sc = malloc(sizeof(struct screenblankenv_so
ftc), M_DEVBUF, M_WAITOK);

..now to get my device actually working