Re: [Xen-devel] [PATCH] Paravirt framebuffer console cleanups [5/5]

[Steven Smith <sos22-xen@xxxxxxxxxxxxx>]

> If we're not set up to use a graphical console for the guest, then we
> need to ensure that the xvc console ends up as the primary console.
> This also should make it so that we can lose the console_use_vt bits.  
> 
> Changes from last time include adding the same bits for x86_64 and ia64
> 
> Signed-off-by: Jeremy Katz <katzj@xxxxxxxxxx>

> diff -r c859588adc5e -r 72582b968445 
> linux-2.6-xen-sparse/arch/i386/kernel/setup-xen.c
> --- a/linux-2.6-xen-sparse/arch/i386/kernel/setup-xen.c       Sat Sep 02 
> 15:31:29 2006 -0400
> +++ b/linux-2.6-xen-sparse/arch/i386/kernel/setup-xen.c       Sat Sep 02 
> 15:32:38 2006 -0400
> @@ -1868,9 +1868,6 @@ void __init setup_arch(char **cmdline_p)
>       } else {
>  #if defined(CONFIG_VT) && defined(CONFIG_DUMMY_CONSOLE)
>               conswitchp = &dummy_con;
> -#else
> -             extern int console_use_vt;
> -             console_use_vt = 0;
>  #endif
>       }
>  }
> diff -r c859588adc5e -r 72582b968445 
> linux-2.6-xen-sparse/arch/ia64/kernel/setup.c
> --- a/linux-2.6-xen-sparse/arch/ia64/kernel/setup.c   Sat Sep 02 15:31:29 
> 2006 -0400
> +++ b/linux-2.6-xen-sparse/arch/ia64/kernel/setup.c   Sat Sep 02 15:32:38 
> 2006 -0400
> @@ -546,9 +546,9 @@ setup_arch (char **cmdline_p)
>                      xen_start_info->nr_pages, xen_start_info->flags);
>  
>               if (!is_initial_xendomain()) {
> -                     extern int console_use_vt;
> +#if !defined(CONFIG_VT) || !defined(CONFIG_DUMMY_CONSOLE)
>                       conswitchp = NULL;
> -                     console_use_vt = 0;
> +#endif
>               }
>       }
>  #endif
> diff -r c859588adc5e -r 72582b968445 
> linux-2.6-xen-sparse/arch/x86_64/kernel/setup-xen.c
> --- a/linux-2.6-xen-sparse/arch/x86_64/kernel/setup-xen.c     Sat Sep 02 
> 15:31:29 2006 -0400
> +++ b/linux-2.6-xen-sparse/arch/x86_64/kernel/setup-xen.c     Sat Sep 02 
> 15:32:38 2006 -0400
> @@ -987,9 +987,10 @@ void __init setup_arch(char **cmdline_p)
>  #endif
>  #endif
>               } else {
> -                     extern int console_use_vt;
> -                     console_use_vt = 0;
> -             }
> +#if defined(CONFIG_VT) && defined(CONFIG_DUMMY_CONSOLE)
> +                    conswitchp = &dummy_con;
> +#endif
> +                }
>       }
>  #else        /* CONFIG_XEN */
>  
> diff -r c859588adc5e -r 72582b968445 
> linux-2.6-xen-sparse/drivers/char/tty_io.c
> --- a/linux-2.6-xen-sparse/drivers/char/tty_io.c      Sat Sep 02 15:31:29 
> 2006 -0400
> +++ b/linux-2.6-xen-sparse/drivers/char/tty_io.c      Sat Sep 02 15:32:38 
> 2006 -0400

It looks to me like this patch makes tty_io.c identical to the
upstream version.  Is this correct?

> @@ -132,8 +132,6 @@ LIST_HEAD(tty_drivers);                   /* linked list
>     vt.c for deeply disgusting hack reasons */
>  DECLARE_MUTEX(tty_sem);
>  
> -int console_use_vt = 1;
> -
>  #ifdef CONFIG_UNIX98_PTYS
>  extern struct tty_driver *ptm_driver;        /* Unix98 pty masters; for 
> /dev/ptmx */
>  extern int pty_limit;                /* Config limit on Unix98 ptys */
> @@ -2056,7 +2054,7 @@ retry_open:
>               goto got_driver;
>       }
>  #ifdef CONFIG_VT
> -     if (console_use_vt && (device == MKDEV(TTY_MAJOR,0))) {
> +     if (device == MKDEV(TTY_MAJOR,0)) {
>               extern struct tty_driver *console_driver;
>               driver = console_driver;
>               index = fg_console;
> @@ -3243,8 +3241,6 @@ static int __init tty_init(void)
>  #endif
>  
>  #ifdef CONFIG_VT
> -     if (!console_use_vt)
> -             goto out_vt;
You can also get rid of the out_vt label.

>       cdev_init(&vc0_cdev, &console_fops);
>       if (cdev_add(&vc0_cdev, MKDEV(TTY_MAJOR, 0), 1) ||
>           register_chrdev_region(MKDEV(TTY_MAJOR, 0), 1, "/dev/vc/0") < 0)
> diff -r c859588adc5e -r 72582b968445 
> linux-2.6-xen-sparse/drivers/xen/console/console.c
> --- a/linux-2.6-xen-sparse/drivers/xen/console/console.c      Sat Sep 02 
> 15:31:29 2006 -0400
> +++ b/linux-2.6-xen-sparse/drivers/xen/console/console.c      Sat Sep 02 
> 15:32:38 2006 -0400
> @@ -663,6 +663,20 @@ static int __init xencons_init(void)
>       printk("Xen virtual console successfully installed as %s%d\n",
>              DRV(xencons_driver)->name, xc_num);
>  
> +        /* Don't need to check about graphical fb for domain 0 */
> +        if (is_initial_xendomain())
> +       return 0;
> +
> +     rc = 0;
> +     if (xenbus_scanf(XBT_NIL, "console", "use_graphics", "%d", &rc) < 0)
> +             printk(KERN_ERR "Unable to read console/use_graphics\n");
> +     if (rc == 0) {
> +               /* FIXME: this is ugly */
> +            unregister_console(&kcons_info);
> +            kcons_info.flags |= CON_CONSDEV;
> +            register_console(&kcons_info);
> +     }
> +
Could you pull the setting of CON_CONSDEV into xen_console_init and
avoid this weirdness?

This whole passage is a little peculiar, in that you're only going to
do anything if use_graphics is disabled.  I'd expect that just leaving
the current behaviour alone would be the correct thing to do in that
case.

Also, why do you need to set CON_CONSDEV at all?

>       return 0;
>  }
>  

Steven.

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