Re: [Qemu-devel] PATCH: fix bgr color mapping on qemu on Solaris/SPARC

[Anthony Liguori <aliguori@us.ibm.com>]

Ben Taylor wrote:
> Enclosed is a patch that fixes the color mapping when running qemu on a Solaris/Sparc
> system.  To enable the color mapping bgr, call qemu with the flag "-bgr".
>
> This patch *requires* the qemu-0.8.1cvs-sparc-solaris.patch diff that was posted
> earlier today.
>
> I separated out this patch as there has been much discussion about fixing the bgr
> problem, but I haven't seen any other code posted.  This has been tested with
> Win98SE and DamnSmallLinux on an Ultra 80 running Solaris 10.
>
> Note:  VNC and Sparc are still not playing nicely, so you will see inverted colors if
> you run qemu on a Solaris Sparc host and display with vnc.
>   

This is going to almost certainly going to have a negative performance 
consequence.  A better solution would be introduce a second set of 
functions that were byte swapped and set the rgb_to_pixel function 
pointer appropriately if bgr is enabled.

I would expect that you can automate the selecting of bgr too based on 
the host architecture and the target architecture.  There shouldn't be a 
need for a new command line option.

If you added a byte_order member to the DisplayState, this would fix the 
vnc case too.

Regards,

Anthony Liguori

> Ben
> ------------------------------------------------------------------------
>
> diff -ruN qemu-solaris-sparc/hw/vga.c qemu/hw/vga.c
> --- qemu-solaris-sparc/hw/vga.c	2006-04-08 21:06:34.000000000 -0400
> +++ qemu/hw/vga.c	2006-05-10 12:31:31.059297000 -0400
> @@ -790,23 +790,43 @@
>  
>  static inline unsigned int rgb_to_pixel8(unsigned int r, unsigned int g, unsigned b)
>  {
> +if (bgr_display_enabled) {
> +    return ((b >> 5) << 5) | ((g >> 5) << 2) | (r >> 6);
> +}
> +else {
>      return ((r >> 5) << 5) | ((g >> 5) << 2) | (b >> 6);
>  }
> +}
>  
>  static inline unsigned int rgb_to_pixel15(unsigned int r, unsigned int g, unsigned b)
>  {
> +if (bgr_display_enabled) {
> +    return ((b >> 3) << 10) | ((g >> 3) << 5) | (r >> 3);
> +}
> +else {
>      return ((r >> 3) << 10) | ((g >> 3) << 5) | (b >> 3);
>  }
> +}
>  
>  static inline unsigned int rgb_to_pixel16(unsigned int r, unsigned int g, unsigned b)
>  {
> +if (bgr_display_enabled) {
> +    return ((b >> 3) << 11) | ((g >> 2) << 5) | (r >> 3);
> +}
> +else {
>      return ((r >> 3) << 11) | ((g >> 2) << 5) | (b >> 3);
>  }
> +}
>  
>  static inline unsigned int rgb_to_pixel32(unsigned int r, unsigned int g, unsigned b)
>  {
> +if (bgr_display_enabled) {
> +    return (b << 16) | (g << 8) | r;
> +}
> +else {
>      return (r << 16) | (g << 8) | b;
>  }
> +}
>  
>  #define DEPTH 8
>  #include "vga_template.h"
> @@ -1366,6 +1386,8 @@
>  
>      if (disp_width != s->last_width ||
>          height != s->last_height) {
> +        if (cirrus_vga_enabled && s->get_bpp(s) >= 8)
> +            memset(s->vram_ptr, 0xff, s->vram_size);
>          dpy_resize(s->ds, disp_width, height);
>          s->last_scr_width = disp_width;
>          s->last_scr_height = height;
> diff -ruN qemu-solaris-sparc/vl.c qemu/vl.c
> --- qemu-solaris-sparc/vl.c	2006-05-10 12:37:40.467126000 -0400
> +++ qemu/vl.c	2006-05-10 12:31:46.354278000 -0400
> @@ -130,6 +130,7 @@
>  int vm_running;
>  int rtc_utc = 1;
>  int cirrus_vga_enabled = 1;
> +int bgr_display_enabled = 0;
>  #ifdef TARGET_SPARC
>  int graphic_width = 1024;
>  int graphic_height = 768;
> @@ -4626,6 +4627,7 @@
>             "-m megs         set virtual RAM size to megs MB [default=%d]\n"
>             "-smp n          set the number of CPUs to 'n' [default=1]\n"
>             "-nographic      disable graphical output and redirect serial I/Os to console\n"
> +           "-bgr            invert colors for HOSTS using certain SPARC frame buffers\n"
>  #ifndef _WIN32
>  	   "-k language     use keyboard layout (for example \"fr\" for French)\n"
>  #endif
> @@ -4782,6 +4784,7 @@
>      QEMU_OPTION_cirrusvga,
>      QEMU_OPTION_g,
>      QEMU_OPTION_std_vga,
> +    QEMU_OPTION_bgr,
>      QEMU_OPTION_monitor,
>      QEMU_OPTION_serial,
>      QEMU_OPTION_parallel,
> @@ -4861,6 +4864,7 @@
>      { "full-screen", 0, QEMU_OPTION_full_screen },
>      { "pidfile", HAS_ARG, QEMU_OPTION_pidfile },
>      { "win2k-hack", 0, QEMU_OPTION_win2k_hack },
> +    { "bgr", 0, QEMU_OPTION_bgr },
>      { "usbdevice", HAS_ARG, QEMU_OPTION_usbdevice },
>      { "smp", HAS_ARG, QEMU_OPTION_smp },
>      { "vnc", HAS_ARG, QEMU_OPTION_vnc },
> @@ -5365,6 +5369,9 @@
>              case QEMU_OPTION_std_vga:
>                  cirrus_vga_enabled = 0;
>                  break;
> +            case QEMU_OPTION_bgr:
> +                bgr_display_enabled = 1;
> +                break;
>              case QEMU_OPTION_g:
>                  {
>                      const char *p;
> diff -ruN qemu-solaris-sparc/vl.h qemu/vl.h
> --- qemu-solaris-sparc/vl.h	2006-05-03 18:02:44.000000000 -0400
> +++ qemu/vl.h	2006-05-10 12:31:51.368923000 -0400
> @@ -135,6 +135,7 @@
>  extern int bios_size;
>  extern int rtc_utc;
>  extern int cirrus_vga_enabled;
> +extern int bgr_display_enabled;
>  extern int graphic_width;
>  extern int graphic_height;
>  extern int graphic_depth;
>   
> ------------------------------------------------------------------------
>
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