On Mon, Jul 14, 2014 at 05:42:22PM +0000, Nathan Whitehorn wrote: > 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); > +} > + Could you use pmap_change_attr() ? This would save some KVA.
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