[Qemu-devel] [PATCH] fix ncurses output

[Qemu-devel] [PATCH] fix ncurses output

[Bernhard Kauer]

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The ncurses console uses mvwaddchnstr() to print a line of output
to a ncurses pad. Unfortunately this routine stops to print further
chars if a zero-char is seen in the line. This has the effect that
parts of a line are never redraw.

The following patch puts spaces instead of the zeros into the line-buffer.
Please note that this change affects other consoles as well and is
perhaps undesirable. Comments?


	Bernhard Kauer

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Index: console.h
--- console.h	10 Feb 2008 16:33:13 -0000	1.2
+++ console.h	25 Feb 2008 17:25:53 -0000
@@ -104,7 +104,8 @@
 typedef unsigned long console_ch_t;
 static inline void console_write_ch(console_ch_t *dest, uint32_t ch)
 {
-    cpu_to_le32wu((uint32_t *) dest, ch);
+  if (!(ch & 0xff))  ch = 0x20;
+  cpu_to_le32wu((uint32_t *) dest, ch);
 }
 
 typedef void (*vga_hw_update_ptr)(void *);

Re: [Qemu-devel] [PATCH] fix ncurses output

[Aurelien Jarno]

On Mon, Feb 25, 2008 at 06:48:06PM +0100, Bernhard Kauer wrote:
> The ncurses console uses mvwaddchnstr() to print a line of output
> to a ncurses pad. Unfortunately this routine stops to print further
> chars if a zero-char is seen in the line. This has the effect that
> parts of a line are never redraw.

Do you have a simple testcase (program to run, code, ...). I have been
unable to reproduce this problem here.

> The following patch puts spaces instead of the zeros into the line-buffer.
> Please note that this change affects other consoles as well and is
> perhaps undesirable. Comments?

I am not sure replacing zeros into spaces is correct. Zeros are not
supposed to be displayed, contrary to spaces.

Aurelien
 
> Index: console.h
> --- console.h	10 Feb 2008 16:33:13 -0000	1.2
> +++ console.h	25 Feb 2008 17:25:53 -0000
> @@ -104,7 +104,8 @@
>  typedef unsigned long console_ch_t;
>  static inline void console_write_ch(console_ch_t *dest, uint32_t ch)
>  {
> -    cpu_to_le32wu((uint32_t *) dest, ch);
> +  if (!(ch & 0xff))  ch = 0x20;
> +  cpu_to_le32wu((uint32_t *) dest, ch);
>  }
>  
>  typedef void (*vga_hw_update_ptr)(void *);


-- 
  .''`.  Aurelien Jarno	            | GPG: 1024D/F1BCDB73
 : :' :  Debian developer           | Electrical Engineer
 `. `'   aurel32@debian.org         | aurelien@aurel32.net
   `-    people.debian.org/~aurel32 | www.aurel32.net

Re: [Qemu-devel] [PATCH] fix ncurses output

[Bernhard Kauer]

On Wed, Mar 12, 2008 at 01:34:04AM +0100, Aurelien Jarno wrote:
> On Mon, Feb 25, 2008 at 06:48:06PM +0100, Bernhard Kauer wrote:
> > The ncurses console uses mvwaddchnstr() to print a line of output
> > to a ncurses pad. Unfortunately this routine stops to print further
> > chars if a zero-char is seen in the line. This has the effect that
> > parts of a line are never redraw.
> 
> Do you have a simple testcase (program to run, code, ...). I have been
> unable to reproduce this problem here.

I didnot have an easy testcase yet, but it will happen if someone clears
the VGA screen with zeros and tries to display a char later on the line.

For the behaviour of the mvwaddchnstr() function see the ncurses source.


    Bernhard
    

Re: [Qemu-devel] [PATCH] fix ncurses output

[Bernhard Kauer]

This bug is still present. Somebody willing to fix it?


	Bernhard


On Mon, Feb 25, 2008 at 06:48:06PM +0100, Bernhard Kauer wrote:
> The ncurses console uses mvwaddchnstr() to print a line of output
> to a ncurses pad. Unfortunately this routine stops to print further
> chars if a zero-char is seen in the line. This has the effect that
> parts of a line are never redraw.
> 
> The following patch puts spaces instead of the zeros into the line-buffer.
> Please note that this change affects other consoles as well and is
> perhaps undesirable. Comments?
> 
> 
> 	Bernhard Kauer

> Index: console.h
> --- console.h	10 Feb 2008 16:33:13 -0000	1.2
> +++ console.h	25 Feb 2008 17:25:53 -0000
> @@ -104,7 +104,8 @@
>  typedef unsigned long console_ch_t;
>  static inline void console_write_ch(console_ch_t *dest, uint32_t ch)
>  {
> -    cpu_to_le32wu((uint32_t *) dest, ch);
> +  if (!(ch & 0xff))  ch = 0x20;
> +  cpu_to_le32wu((uint32_t *) dest, ch);
>  }
>  
>  typedef void (*vga_hw_update_ptr)(void *);