Author: nwhitehorn
Date: Mon Jul 14 17:42:22 2014
New Revision: 268624
URL: http://svnweb.freebsd.org/changeset/base/268624
Log:
On my Lenovo laptop, the firmware maps the EFI framebuffer with MTRRs set
to uncacheable. This leads to execrable console performance. Once PMAP is
up, remap the framebuffer as write-combining. This reduces boot time on my
laptop by 60% when booting with EFI.
MFC after: 2 weeks
Modified:
head/sys/dev/vt/hw/efifb/efifb.c
Modified: head/sys/dev/vt/hw/efifb/efifb.c
==============================================================================
--- head/sys/dev/vt/hw/efifb/efifb.c Mon Jul 14 17:16:09 2014
(r268623)
+++ head/sys/dev/vt/hw/efifb/efifb.c Mon Jul 14 17:42:22 2014
(r268624)
@@ -53,6 +53,7 @@ __FBSDID("$FreeBSD$");
static vd_init_t vt_efifb_init;
static vd_probe_t vt_efifb_probe;
+static void vt_efifb_remap(void *efifb_data);
static struct vt_driver vt_efifb_driver = {
.vd_name = "efifb",
@@ -68,6 +69,8 @@ static struct vt_driver vt_efifb_driver
static struct fb_info local_info;
VT_DRIVER_DECLARE(vt_efifb, vt_efifb_driver);
+SYSINIT(efifb_remap, SI_SUB_KMEM, SI_ORDER_ANY, vt_efifb_remap, &local_info);
+
static int
vt_efifb_probe(struct vt_device *vd)
{
@@ -133,9 +136,9 @@ vt_efifb_init(struct vt_device *vd)
info->fb_size = info->fb_height * info->fb_stride;
info->fb_pbase = efifb->fb_addr;
/*
- * We could use pmap_mapdev here except that the kernel pmap
- * hasn't been created yet and hence any attempt to lock it will
- * fail.
+ * Use the direct map as a crutch until pmap is available. Once pmap
+ * is online, the framebuffer will be remapped by vt_efifb_remap()
+ * using pmap_mapdev_attr().
*/
info->fb_vbase = PHYS_TO_DMAP(efifb->fb_addr);
@@ -163,3 +166,22 @@ vt_efifb_init(struct vt_device *vd)
return (CN_INTERNAL);
}
+
+static void
+vt_efifb_remap(void *xinfo)
+{
+ struct fb_info *info = xinfo;
+
+ if (info->fb_pbase == 0)
+ return;
+
+ /*
+ * Remap as write-combining. This massively improves performance and
+ * happens very early in kernel initialization, when everything is
+ * still single-threaded and interrupts are off, so replacing the
+ * mapping address is safe.
+ */
+ info->fb_vbase = (intptr_t)pmap_mapdev_attr(info->fb_pbase,
+ info->fb_size, VM_MEMATTR_WRITE_COMBINING);
+}
+
