Messages in this thread | | | Date | Mon, 26 Apr 2010 12:36:05 +0300 | From | Pekka Enberg <> | 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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Guenter Roeck kirjoitti: > 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); > + } > } > > 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;
Wouldn't it be better to switch to, say, serial console here to avoid the NULL check in early_printk()?
> + > return 0; > } >
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