[20/21] udlfb: avoid prefetch

Commit Message

Mikulas Patocka June 3, 2018, 2:41 p.m. UTC

Modern processors can detect linear memory accesses and prefetch data
automatically, so there's no need to use prefetch.

Signed-off-by: Mikulas Patocka <[e-mail]>

---
 drivers/video/fbdev/udlfb.c |    8 --------
 1 file changed, 8 deletions(-)

Patch

Index: linux-4.17-rc7/drivers/video/fbdev/udlfb.c
===================================================================
--- linux-4.17-rc7.orig/drivers/video/fbdev/udlfb.c	2018-05-31 12:48:35.000000000 +0200
+++ linux-4.17-rc7/drivers/video/fbdev/udlfb.c	2018-05-31 12:48:35.000000000 +0200
@@ -25,7 +25,6 @@ 
 #include <linux/fb.h>
 #include <linux/vmalloc.h>
 #include <linux/slab.h>
-#include <linux/prefetch.h>
 #include <linux/delay.h>
 #include <asm/unaligned.h>
 #include <video/udlfb.h>
@@ -375,9 +374,6 @@  static int dlfb_trim_hline(const u8 *bba
 	int start = width;
 	int end = width;
 
-	prefetch((void *) front);
-	prefetch((void *) back);
-
 	for (j = 0; j < width; j++) {
 		if (back[j] != front[j]) {
 			start = j;
@@ -454,8 +450,6 @@  static void dlfb_compress_hline(
 			continue;
 		}
 
-		prefetchw((void *) cmd); /* pull in one cache line at least */
-
 		*cmd++ = 0xAF;
 		*cmd++ = 0x6B;
 		*cmd++ = dev_addr >> 16;
@@ -479,8 +473,6 @@  static void dlfb_compress_hline(
 				cmd_pixel_end--;
 		}
 
-		prefetch_range((void *) pixel, (u8 *)cmd_pixel_end - (u8 *)pixel);
-
 		while (pixel < cmd_pixel_end) {
 			const uint16_t * const repeating_pixel = pixel;
 			u16 pixel_value = *pixel;