Messages in this thread | | | Date | Mon, 26 Apr 2010 09:11:20 -0700 | From | Guenter Roeck <> | Subject | Re: [PATCH v3] x86: Do not write into VGA memory space if there is no VGA device in the system |
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On Mon, Apr 26, 2010 at 11:43:44AM -0400, Bastien ROUCARIES wrote: > On Tue, Apr 20, 2010 at 6:16 PM, Guenter Roeck > <guenter.roeck@ericsson.com> wrote: > > Ensure that early_printk() does not write into VGA memory space > > if there is not VGA device in the system. > > > > Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com> > > --- > > v3: > > Changes are now limited to early_printk.c. Functionality is retained, meaning > > there will still be output on the VGA console before setup_early_printk() > > is called, but only if a VGA device is known to exist in the system. > > > > arch/x86/kernel/early_printk.c | 17 +++++++++++++---- > > 1 files changed, 13 insertions(+), 4 deletions(-) > > > > diff --git a/arch/x86/kernel/early_printk.c b/arch/x86/kernel/early_printk.c > > index b9c830c..783cb25 100644 > > --- a/arch/x86/kernel/early_printk.c > > +++ b/arch/x86/kernel/early_printk.c > > @@ -170,10 +170,13 @@ asmlinkage void early_printk(const char *fmt, ...) > > int n; > > va_list ap; > > > > - va_start(ap, fmt); > > - n = vscnprintf(buf, sizeof(buf), fmt, ap); > > - early_console->write(early_console, buf, n); > > - va_end(ap); > > + if (early_console && (early_console_initialized || > > + boot_params.screen_info.orig_video_isVGA == 1)) { > > + va_start(ap, fmt); > > + n = vscnprintf(buf, sizeof(buf), fmt, ap); > > + early_console->write(early_console, buf, n); > > + va_end(ap); > > + } > > } > > Instead to this ugly if why not creating a null early_console (write > will do nothing) ? > > > static inline void early_console_register(struct console *con, int keep_early) > > @@ -233,6 +236,12 @@ static int __init setup_early_printk(char *buf) > > #endif > > buf++; > > } > > + > > + /* If there is no VGA device, don't try to use it as early console. */ > > + if (early_console == &early_vga_console && > > + boot_params.screen_info.orig_video_isVGA != 1) > > + early_console = NULL; > > + > > return 0; > > } > > And assign null console as the last console as a fallback ? > Sounds good to me. Peter, would that get your approval ?
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