[PATCH] parisc: pass through '\t' to early (iodc) console

[PATCH] parisc: pass through '\t' to early (iodc) console

[Kyle McMartin]

The firmware handles '\t' internally, so stop trying to emulate it
(which, incidentally, had a bug in it.)

Fixes a really weird hang at bootup in rcu_bootup_announce, which,
as far as I can tell, is the first printk in the core kernel to use
a tab as the first character.

Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
---
 arch/parisc/kernel/firmware.c |   12 ++----------
 1 files changed, 2 insertions(+), 10 deletions(-)

diff --git a/arch/parisc/kernel/firmware.c b/arch/parisc/kernel/firmware.c
index 4c247e0..df971fa 100644
--- a/arch/parisc/kernel/firmware.c
+++ b/arch/parisc/kernel/firmware.c
@@ -1123,7 +1123,6 @@ static char __attribute__((aligned(64))) iodc_dbuf[4096];
  */
 int pdc_iodc_print(const unsigned char *str, unsigned count)
 {
-	static int posx;        /* for simple TAB-Simulation... */
 	unsigned int i;
 	unsigned long flags;
 
@@ -1133,19 +1132,12 @@ int pdc_iodc_print(const unsigned char *str, unsigned count)
 			iodc_dbuf[i+0] = '\r';
 			iodc_dbuf[i+1] = '\n';
 			i += 2;
-			posx = 0;
 			goto print;
-		case '\t':
-			while (posx & 7) {
-				iodc_dbuf[i] = ' ';
-				i++, posx++;
-			}
-			break;
 		case '\b':	/* BS */
-			posx -= 2;
+			i--; /* overwrite last */
 		default:
 			iodc_dbuf[i] = str[i];
-			i++, posx++;
+			i++;
 			break;
 		}
 	}
-- 
1.7.0.1

Re: [PATCH] parisc: pass through '\t' to early (iodc) console

[Helge Deller]

On 06/14/2010 06:02 PM, Kyle McMartin wrote:
> The firmware handles '\t' internally, so stop trying to emulate it
> (which, incidentally, had a bug in it.)
> 
> Fixes a really weird hang at bootup in rcu_bootup_announce, which,
> as far as I can tell, is the first printk in the core kernel to use
> a tab as the first character.
> 
> Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>

Kernel boots now nicely.
Thanks Kyle!

Tested-by: Helge Deller <deller@gmx.de>


> ---
>  arch/parisc/kernel/firmware.c |   12 ++----------
>  1 files changed, 2 insertions(+), 10 deletions(-)
> 
> diff --git a/arch/parisc/kernel/firmware.c b/arch/parisc/kernel/firmware.c
> index 4c247e0..df971fa 100644
> --- a/arch/parisc/kernel/firmware.c
> +++ b/arch/parisc/kernel/firmware.c
> @@ -1123,7 +1123,6 @@ static char __attribute__((aligned(64))) iodc_dbuf[4096];
>   */
>  int pdc_iodc_print(const unsigned char *str, unsigned count)
>  {
> -	static int posx;        /* for simple TAB-Simulation... */
>  	unsigned int i;
>  	unsigned long flags;
>  
> @@ -1133,19 +1132,12 @@ int pdc_iodc_print(const unsigned char *str, unsigned count)
>  			iodc_dbuf[i+0] = '\r';
>  			iodc_dbuf[i+1] = '\n';
>  			i += 2;
> -			posx = 0;
>  			goto print;
> -		case '\t':
> -			while (posx & 7) {
> -				iodc_dbuf[i] = ' ';
> -				i++, posx++;
> -			}
> -			break;
>  		case '\b':	/* BS */
> -			posx -= 2;
> +			i--; /* overwrite last */
>  		default:
>  			iodc_dbuf[i] = str[i];
> -			i++, posx++;
> +			i++;
>  			break;
>  		}
>  	}

[PATCH] parisc: pass through '\t' to early (iodc) console

[Kyle McMartin]

The firmware handles '\t' internally, so stop trying to emulate it
(which, incidentally, had a bug in it.)

Fixes a really weird hang at bootup in rcu_bootup_announce, which,
as far as I can tell, is the first printk in the core kernel to use
a tab as the first character.

Cc: stable@kernel.org
Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
---

Oops, looks like this slipped through the cracks in my summer
vacation. Resending for 2.6.36 and stable kernels...

 arch/parisc/kernel/firmware.c |   12 ++----------
 1 files changed, 2 insertions(+), 10 deletions(-)

diff --git a/arch/parisc/kernel/firmware.c b/arch/parisc/kernel/firmware.c
index 4c247e0..df971fa 100644
--- a/arch/parisc/kernel/firmware.c
+++ b/arch/parisc/kernel/firmware.c
@@ -1123,7 +1123,6 @@ static char __attribute__((aligned(64))) iodc_dbuf[4096];
  */
 int pdc_iodc_print(const unsigned char *str, unsigned count)
 {
-	static int posx;        /* for simple TAB-Simulation... */
 	unsigned int i;
 	unsigned long flags;
 
@@ -1133,19 +1132,12 @@ int pdc_iodc_print(const unsigned char *str, unsigned count)
 			iodc_dbuf[i+0] = '\r';
 			iodc_dbuf[i+1] = '\n';
 			i += 2;
-			posx = 0;
 			goto print;
-		case '\t':
-			while (posx & 7) {
-				iodc_dbuf[i] = ' ';
-				i++, posx++;
-			}
-			break;
 		case '\b':	/* BS */
-			posx -= 2;
+			i--; /* overwrite last */
 		default:
 			iodc_dbuf[i] = str[i];
-			i++, posx++;
+			i++;
 			break;
 		}
 	}
-- 
1.7.0.1