[PATCH] move DAC register setting to linux.c

[Robert Millan <rmh@aybabtu.com>]

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It didn't really seem right that we were *setting* values in the DAC palette
register in a function that was only meant to retrieve video mode information.

So I would rather move this to the Linux loader.  In the event that other
loaders would need this facility, it can be moved into a shared function.

This has the advantage that we don't mess with the DAC palette in cases where
this is not necessary (read: the vast majority of them).

-- 
Robert Millan

  The DRM opt-in fallacy: "Your data belongs to us. We will decide when (and
  how) you may access your data; but nobody's threatening your freedom: we
  still allow you to remove your data and not access it at all."

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2009-09-10  Robert Millan  <rmh.grub@aybabtu.com>

	* video/i386/pc/vbe.c (grub_vbe_get_video_mode_info): Move packed
	mode special handling (grub_vbe_bios_set_dac_palette_width() call)
	from here ...
	* loader/i386/linux.c [GRUB_MACHINE_PCBIOS]
	(grub_linux_setup_video): ... to here (with some adjustments).

Index: video/i386/pc/vbe.c
===================================================================
--- video/i386/pc/vbe.c	(revision 2583)
+++ video/i386/pc/vbe.c	(working copy)
@@ -286,24 +286,6 @@ grub_vbe_get_video_mode_info (grub_uint3
 
       /* Make copy of mode info block.  */
       grub_memcpy (mode_info, mi_tmp, sizeof (*mode_info));
-
-      /* Packed mode.  Query DAC Palette width for color sizes.  */
-      if (mode_info->bits_per_pixel <= 8)
-	{
-	  int width = 8;
-	  status = 0;
-
-	  if (controller_info.capabilities & GRUB_VBE_CAPABILITY_DACWIDTH)
-	    status = grub_vbe_bios_set_dac_palette_width (& width);
-
-	  if (status != GRUB_VBE_STATUS_OK)
-	    /* 6 is default after mode reset.  */
-	    width = 6;
-
-	  mode_info->red_mask_size = mode_info->green_mask_size
-	    = mode_info->blue_mask_size = width;
-	  mode_info->rsvd_mask_size = 0;
-	}
     }
   else
     /* Just clear mode info block if it isn't a VESA mode.  */
Index: loader/i386/linux.c
===================================================================
--- loader/i386/linux.c	(revision 2583)
+++ loader/i386/linux.c	(working copy)
@@ -33,6 +33,7 @@
 #include <grub/video.h>
 #include <grub/video_fb.h>
 #include <grub/command.h>
+#include <grub/i386/pc/vbe.h>
 
 #define GRUB_LINUX_CL_OFFSET		0x1000
 #define GRUB_LINUX_CL_END_OFFSET	0x2000
@@ -416,6 +417,33 @@ grub_linux_setup_video (struct linux_ker
   params->reserved_mask_size = mode_info.reserved_mask_size;
   params->reserved_field_pos = mode_info.reserved_field_pos;
 
+
+#ifdef GRUB_MACHINE_PCBIOS
+  /* VESA packed modes may come with zeroed mask sizes, which need
+     to be set here according to DAC Palette width.  If we don't,
+     this results in Linux displaying a black screen.  */
+  if (mode_info.bpp <= 8)
+    {
+      struct grub_vbe_info_block controller_info;
+      int status;
+      int width = 8;
+
+      status = grub_vbe_bios_get_controller_info (&controller_info);
+
+      if (status == GRUB_VBE_STATUS_OK &&
+	  (controller_info.capabilities & GRUB_VBE_CAPABILITY_DACWIDTH))
+	status = grub_vbe_bios_set_dac_palette_width (&width);
+
+      if (status != GRUB_VBE_STATUS_OK)
+	/* 6 is default after mode reset.  */
+	width = 6;
+
+      params->red_mask_size = params->green_mask_size
+	= params->blue_mask_size = width;
+      params->reserved_mask_size = 0;
+    }
+#endif
+
   return 0;
 }