PATCH: Make sysfs color_map attribute work

[Jon Smirl <jonsmirl@gmail.com>]

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These two patches make the sysfs color_map attribute work. There is a
minor bug in sysfs fixed by sysfs_offbyone.patch. I sent the sysfs fix
separately to GregKH.

Sysfs usually works in text instead of binary. That lets scripts set
the attributes. You can set an attribute from a program with normal
file writes. The values have to be less than PAGE_SIZE in size.

Color maps have up to 256 entries. 4096/256 allows for 16 characters per line.

The format for a cmap entry is "%02x%c%4x%4x%4x\n"
%02x entry %c transp %4x red %4x blue %4x green

You don't have to start at zero, you can change one or more entries
this way. Build up a line per entry and set the whole block into the
attribute.

You can read the color_map with cat fb0/color_map.

My assumption from looking at the code that transparent is a boolean
flag. If the "%c" column is not a space transparent will be set for
that entry.

-- 
Jon Smirl
jonsmirl@gmail.com

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[-- Attachment #2: sysfs_offbyone.patch --]
[-- Type: text/x-diff; name="sysfs_offbyone.patch", Size: 362 bytes --]

diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
--- a/fs/sysfs/file.c
+++ b/fs/sysfs/file.c
@@ -182,7 +182,7 @@ fill_write_buffer(struct sysfs_buffer * 
 		return -ENOMEM;
 
 	if (count >= PAGE_SIZE)
-		count = PAGE_SIZE - 1;
+		count = PAGE_SIZE;
 	error = copy_from_user(buffer->page,buf,count);
 	buffer->needs_read_fill = 1;
 	return error ? -EFAULT : count;

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[-- Attachment #3: cmap_sysfs.patch --]
[-- Type: text/x-diff; name="cmap_sysfs.patch", Size: 3384 bytes --]

diff --git a/drivers/video/fbsysfs.c b/drivers/video/fbsysfs.c
--- a/drivers/video/fbsysfs.c
+++ b/drivers/video/fbsysfs.c
@@ -244,10 +242,68 @@ static ssize_t show_virtual(struct class
 			fb_info->var.xres_virtual);
 }
 
-static ssize_t store_cmap(struct class_device *class_device, const char * buf,
+/* Format for cmap is "%02x%c%4x%4x%4x\n" */
+/* %02x entry %c transp %4x red %4x blue %4x green \n */
+/* 255 rows at 16 chars equals 4096 */
+/* PAGE_SIZE can be 4096 or larger */
+static ssize_t store_cmap(struct class_device *class_device, const char *buf,
 			  size_t count)
 {
-//	struct fb_info *fb_info = (struct fb_info *)class_get_devdata(class_device);
+	struct fb_info *fb_info = (struct fb_info *)class_get_devdata(class_device);
+	int rc, i, start, length, transp = 0;
+
+	if ((count > 4096) || ((count % 16) != 0) || (PAGE_SIZE < 4096))
+		return -EINVAL;
+
+	if (!fb_info->fbops->fb_setcolreg && !fb_info->fbops->fb_setcmap)
+		return -EINVAL;
+
+	sscanf(buf, "%02x", &start);
+	length = count / 16;
+
+	for (i = 0; i < length; i++)
+		if (buf[i * 16 + 2] != ' ')
+			transp = 1;
+
+	/* If we can batch, do it */
+	if (fb_info->fbops->fb_setcmap && length > 1) {
+		struct fb_cmap umap;
+
+		memset(&umap, 0, sizeof(umap));
+		if ((rc = fb_alloc_cmap(&umap, length, transp)))
+			return rc;
+
+		umap.start = start;
+		for (i = 0; i < length; i++) {
+			sscanf(&buf[i * 16 +  3], "%4hx", &umap.red[i]);
+			sscanf(&buf[i * 16 +  7], "%4hx", &umap.blue[i]);
+			sscanf(&buf[i * 16 + 11], "%4hx", &umap.green[i]);
+			if (transp)
+				umap.transp[i] = (buf[i * 16 +  2] != ' ');
+		}
+		rc = fb_info->fbops->fb_setcmap(&umap, fb_info);
+		fb_copy_cmap(&umap, &fb_info->cmap);
+		fb_dealloc_cmap(&umap);
+
+		return rc;
+	}
+	for (i = 0; i < length; i++) {
+		u16 red, blue, green, tsp;
+
+		sscanf(&buf[i * 16 +  3], "%4hx", &red);
+		sscanf(&buf[i * 16 +  7], "%4hx", &blue);
+		sscanf(&buf[i * 16 + 11], "%4hx", &green);
+		tsp = (buf[i * 16 +  2] != ' ');
+		if ((rc = fb_info->fbops->fb_setcolreg(start++,
+				      red, green, blue, tsp, fb_info)))
+			return rc;
+
+		fb_info->cmap.red[i] = red;
+		fb_info->cmap.blue[i] = blue;
+		fb_info->cmap.green[i] = green;
+		if (transp)
+			fb_info->cmap.transp[i] = tsp;
+	}
 	return 0;
 }
 
@@ -255,20 +311,24 @@ static ssize_t show_cmap(struct class_de
 {
 	struct fb_info *fb_info =
 		(struct fb_info *)class_get_devdata(class_device);
-	unsigned int offset = 0, i;
+	unsigned int i;
 
 	if (!fb_info->cmap.red || !fb_info->cmap.blue ||
-	    fb_info->cmap.green || fb_info->cmap.transp)
+	    !fb_info->cmap.green)
+		return -EINVAL;
+
+	if (PAGE_SIZE < 4096)
 		return -EINVAL;
 
+	/* don't mess with the format, the buffer is PAGE_SIZE */
+	/* 255 entries at 16 chars per line equals 4096 = PAGE_SIZE */
 	for (i = 0; i < fb_info->cmap.len; i++) {
-		offset += snprintf(buf, PAGE_SIZE - offset,
-				   "%d,%d,%d,%d,%d\n", i + fb_info->cmap.start,
-				   fb_info->cmap.red[i], fb_info->cmap.blue[i],
-				   fb_info->cmap.green[i],
-				   fb_info->cmap.transp[i]);
+		sprintf(&buf[ i * 16], "%02x%c%4x%4x%4x\n", i + fb_info->cmap.start,
+			((fb_info->cmap.transp && fb_info->cmap.transp[i]) ? '*' : ' '),
+			fb_info->cmap.red[i], fb_info->cmap.blue[i],
+			fb_info->cmap.green[i]);
 	}
-	return offset;
+	return 4096;
 }
 
 static ssize_t store_blank(struct class_device *class_device, const char * buf,