diff --git a/Documentation/fb/efifb.txt b/Documentation/fb/efifb.txt index a59916c29b33..1a85c1bdaf38 100644 --- a/Documentation/fb/efifb.txt +++ b/Documentation/fb/efifb.txt @@ -27,5 +27,11 @@ You have to add the following kernel parameters in your elilo.conf: Macbook Pro 17", iMac 20" : video=efifb:i20 +Accepted options: + +nowc Don't map the framebuffer write combined. This can be used + to workaround side-effects and slowdowns on other CPU cores + when large amounts of console data are written. + -- Edgar Hucek diff --git a/drivers/video/fbdev/efifb.c b/drivers/video/fbdev/efifb.c index ff01bed7112f..1e784adb89b1 100644 --- a/drivers/video/fbdev/efifb.c +++ b/drivers/video/fbdev/efifb.c @@ -17,6 +17,7 @@ #include static bool request_mem_succeeded = false; +static bool nowc = false; static struct fb_var_screeninfo efifb_defined = { .activate = FB_ACTIVATE_NOW, @@ -99,6 +100,8 @@ static int efifb_setup(char *options) screen_info.lfb_height = simple_strtoul(this_opt+7, NULL, 0); else if (!strncmp(this_opt, "width:", 6)) screen_info.lfb_width = simple_strtoul(this_opt+6, NULL, 0); + else if (!strcmp(this_opt, "nowc")) + nowc = true; } } @@ -255,7 +258,10 @@ static int efifb_probe(struct platform_device *dev) info->apertures->ranges[0].base = efifb_fix.smem_start; info->apertures->ranges[0].size = size_remap; - info->screen_base = ioremap_wc(efifb_fix.smem_start, efifb_fix.smem_len); + if (nowc) + info->screen_base = ioremap(efifb_fix.smem_start, efifb_fix.smem_len); + else + info->screen_base = ioremap_wc(efifb_fix.smem_start, efifb_fix.smem_len); if (!info->screen_base) { pr_err("efifb: abort, cannot ioremap video memory 0x%x @ 0x%lx\n", efifb_fix.smem_len, efifb_fix.smem_start);