[PATCH] fbdev: fix framebuffer memory calculation for vesafb

- use vesafb_fix.line_length * vesafb_defined.yres to calculate the minimum
  memory required for a video mode. From Aurelien Jacobs <aurel@gnuage.org>.

- separately calculate the memory required for a video mode, memory to be
  remapped, and total memory (for MTRR). From Gerd Knorr
  <kraxel@bytesex.org>.

- the 'vram' option is for memory to be remapped, not total memory.

Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/drivers/video/vesafb.c b/drivers/video/vesafb.c
index c5c649d9b1aebf7fcd0dbbbc84ee2153437a62c8..632ee47b8d70fe22aebf938ed854f2edfbe371a5 100644 (file)
--- a/drivers/video/vesafb.c
+++ b/drivers/video/vesafb.c
@@ -220,6 +220,9 @@ static int __init vesafb_probe(struct device *device)
        struct platform_device *dev = to_platform_device(device);
        struct fb_info *info;
        int i, err;
+       unsigned int size_vmode;
+       unsigned int size_remap;
+       unsigned int size_total;
 
        if (screen_info.orig_video_isVGA != VIDEO_TYPE_VLFB)
                return -ENXIO;
@@ -231,32 +234,37 @@ static int __init vesafb_probe(struct device *device)
        vesafb_defined.xres = screen_info.lfb_width;
        vesafb_defined.yres = screen_info.lfb_height;
        vesafb_fix.line_length = screen_info.lfb_linelength;
-
-       /* Allocate enough memory for double buffering */
-       vesafb_fix.smem_len = screen_info.lfb_width * screen_info.lfb_height * vesafb_defined.bits_per_pixel >> 2;
-
-       /* check that we don't remap more memory than old cards have */
-       if (vesafb_fix.smem_len > (screen_info.lfb_size * 65536))
-               vesafb_fix.smem_len = screen_info.lfb_size * 65536;
-
-       /* Set video size according to vram boot option */
-       if (vram)
-               vesafb_fix.smem_len = vram * 1024 * 1024;
-
        vesafb_fix.visual   = (vesafb_defined.bits_per_pixel == 8) ?
                FB_VISUAL_PSEUDOCOLOR : FB_VISUAL_TRUECOLOR;
 
-       /* limit framebuffer size to 16 MB.  Otherwise we'll eat tons of
-        * kernel address space for nothing if the gfx card has alot of
-        * memory (>= 128 MB isn't uncommon these days ...) */
-       if (vesafb_fix.smem_len > 16 * 1024 * 1024)
-               vesafb_fix.smem_len = 16 * 1024 * 1024;
+       /*   size_vmode -- that is the amount of memory needed for the
+        *                 used video mode, i.e. the minimum amount of
+        *                 memory we need. */
+       size_vmode = vesafb_fix.line_length * vesafb_defined.yres;
+
+       /*   size_total -- all video memory we have. Used for mtrr
+        *                 entries and bounds checking. */
+       size_total = screen_info.lfb_size * 65536;
+       if (size_total < size_vmode)
+               size_total = size_vmode;
+
+       /*   size_remap -- the amount of video memory we are going to
+        *                 use for vesafb.  With modern cards it is no
+        *                 option to simply use size_total as that
+        *                 wastes plenty of kernel address space. */
+       size_remap = size_vmode * 2;
+       if (vram)
+               size_remap = vram * 1024 * 1024;
+
+       if (size_remap > size_total)
+               size_remap = size_total;
+       vesafb_fix.smem_len = size_remap;
 
 #ifndef __i386__
        screen_info.vesapm_seg = 0;
 #endif
 
-       if (!request_mem_region(vesafb_fix.smem_start, vesafb_fix.smem_len, "vesafb")) {
+       if (!request_mem_region(vesafb_fix.smem_start, size_total, "vesafb")) {
                printk(KERN_WARNING
                       "vesafb: abort, cannot reserve video memory at 0x%lx\n",
                        vesafb_fix.smem_start);
@@ -281,8 +289,10 @@ static int __init vesafb_probe(struct device *device)
                goto err;
        }
 
-       printk(KERN_INFO "vesafb: framebuffer at 0x%lx, mapped to 0x%p, size %dk\n",
-              vesafb_fix.smem_start, info->screen_base, vesafb_fix.smem_len/1024);
+       printk(KERN_INFO "vesafb: framebuffer at 0x%lx, mapped to 0x%p, "
+              "using %dk, total %dk\n",
+              vesafb_fix.smem_start, info->screen_base,
+              size_remap/1024, size_total/1024);
        printk(KERN_INFO "vesafb: mode is %dx%dx%d, linelength=%d, pages=%d\n",
               vesafb_defined.xres, vesafb_defined.yres, vesafb_defined.bits_per_pixel, vesafb_fix.line_length, screen_info.pages);
 
@@ -362,7 +372,7 @@ static int __init vesafb_probe(struct device *device)
        request_region(0x3c0, 32, "vesafb");
 
        if (mtrr) {
-               int temp_size = vesafb_fix.smem_len;
+               int temp_size = size_total;
                /* Find the largest power-of-two */
                while (temp_size & (temp_size - 1))
                        temp_size &= (temp_size - 1);
@@ -393,7 +403,7 @@ static int __init vesafb_probe(struct device *device)
        return 0;
 err:
        framebuffer_release(info);
-       release_mem_region(vesafb_fix.smem_start, vesafb_fix.smem_len);
+       release_mem_region(vesafb_fix.smem_start, size_total);
        return err;
 }