This patch appears to introduce a regression on my system(https://www.jetwaycomputer.com/NF9B.html). My board uses an Intel gma3650 GPU. It causes a complete failure of all video output. With it reverted I get: [ 1.169444] efifb: probing for efifb [ 1.169499] efifb: framebuffer at 0xcf800000, using 1876k, total 1875k [ 1.169511] efifb: mode is 800x600x32, linelength=3200, pages=1 [ 1.169519] efifb: scrolling: redraw [ 1.169528] efifb: Truecolor: size=8:8:8:8, shift=24:16:8:0 Without it reverted I get: [ 1.173368] efifb: probing for efifb [ 1.173386] efifb: abort, cannot remap video memory 0x1d5000 @ 0xcf800000 [ 1.173395] Trying to free nonexistent resource <00000000cf800000-00000000cf9d4bff> [ 1.173413] efi-framebuffer: probe of efi-framebuffer.0 failed with error -5 On Wed, Jul 11, 2018 at 11:40 AM Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> wrote: > > If the framebuffer address provided by the Graphics Output Protocol > (GOP) is covered by the UEFI memory map, it will tell us which memory > attributes are permitted when mapping this region. In some cases, > (KVM guest on ARM), violating this will result in loss of coherency, > which means that updates sent to the framebuffer by the guest will > not be observeable by the host, and the emulated display simply does > not work. > > So if the memory map contains such a description, take the attributes > field into account, and add support for creating WT or WB mappings of > the framebuffer region. > > Cc: Peter Jones <pjones@xxxxxxxxxx> > Tested-by: Laszlo Ersek <lersek@xxxxxxxxxx> > Acked-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@xxxxxxxxxxx> > Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> > --- > drivers/video/fbdev/efifb.c | 51 +++++++++++++++++++++++++++++-------- > 1 file changed, 41 insertions(+), 10 deletions(-) > > diff --git a/drivers/video/fbdev/efifb.c b/drivers/video/fbdev/efifb.c > index 46a4484e3da7..c6f78d27947b 100644 > --- a/drivers/video/fbdev/efifb.c > +++ b/drivers/video/fbdev/efifb.c > @@ -20,7 +20,7 @@ > #include <drm/drm_connector.h> /* For DRM_MODE_PANEL_ORIENTATION_* */ > > static bool request_mem_succeeded = false; > -static bool nowc = false; > +static u64 mem_flags = EFI_MEMORY_WC | EFI_MEMORY_UC; > > static struct fb_var_screeninfo efifb_defined = { > .activate = FB_ACTIVATE_NOW, > @@ -68,8 +68,12 @@ static int efifb_setcolreg(unsigned regno, unsigned red, unsigned green, > > static void efifb_destroy(struct fb_info *info) > { > - if (info->screen_base) > - iounmap(info->screen_base); > + if (info->screen_base) { > + if (mem_flags & (EFI_MEMORY_UC | EFI_MEMORY_WC)) > + iounmap(info->screen_base); > + else > + memunmap(info->screen_base); > + } > if (request_mem_succeeded) > release_mem_region(info->apertures->ranges[0].base, > info->apertures->ranges[0].size); > @@ -104,7 +108,7 @@ static int efifb_setup(char *options) > 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; > + mem_flags &= ~EFI_MEMORY_WC; > } > } > > @@ -164,6 +168,7 @@ static int efifb_probe(struct platform_device *dev) > unsigned int size_remap; > unsigned int size_total; > char *option = NULL; > + efi_memory_desc_t md; > > if (screen_info.orig_video_isVGA != VIDEO_TYPE_EFI || pci_dev_disabled) > return -ENODEV; > @@ -272,12 +277,35 @@ static int efifb_probe(struct platform_device *dev) > info->apertures->ranges[0].base = efifb_fix.smem_start; > info->apertures->ranges[0].size = size_remap; > > - 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 (!efi_mem_desc_lookup(efifb_fix.smem_start, &md)) { > + if ((efifb_fix.smem_start + efifb_fix.smem_len) > > + (md.phys_addr + (md.num_pages << EFI_PAGE_SHIFT))) { > + pr_err("efifb: video memory @ 0x%lx spans multiple EFI memory regions\n", > + efifb_fix.smem_start); > + err = -EIO; > + goto err_release_fb; > + } > + /* > + * If the UEFI memory map covers the efifb region, we may only > + * remap it using the attributes the memory map prescribes. > + */ > + mem_flags |= EFI_MEMORY_WT | EFI_MEMORY_WB; > + mem_flags &= md.attribute; > + } > + if (mem_flags & EFI_MEMORY_WC) > + info->screen_base = ioremap_wc(efifb_fix.smem_start, > + efifb_fix.smem_len); > + else if (mem_flags & EFI_MEMORY_UC) > + info->screen_base = ioremap(efifb_fix.smem_start, > + efifb_fix.smem_len); > + else if (mem_flags & EFI_MEMORY_WT) > + info->screen_base = memremap(efifb_fix.smem_start, > + efifb_fix.smem_len, MEMREMAP_WT); > + else if (mem_flags & EFI_MEMORY_WB) > + info->screen_base = memremap(efifb_fix.smem_start, > + efifb_fix.smem_len, MEMREMAP_WB); > if (!info->screen_base) { > - pr_err("efifb: abort, cannot ioremap video memory 0x%x @ 0x%lx\n", > + pr_err("efifb: abort, cannot remap video memory 0x%x @ 0x%lx\n", > efifb_fix.smem_len, efifb_fix.smem_start); > err = -EIO; > goto err_release_fb; > @@ -371,7 +399,10 @@ static int efifb_probe(struct platform_device *dev) > err_groups: > sysfs_remove_groups(&dev->dev.kobj, efifb_groups); > err_unmap: > - iounmap(info->screen_base); > + if (mem_flags & (EFI_MEMORY_UC | EFI_MEMORY_WC)) > + iounmap(info->screen_base); > + else > + memunmap(info->screen_base); > err_release_fb: > framebuffer_release(info); > err_release_mem: > -- > 2.17.1 > > > >
