[PATCH v2] x86:sysfb_efi:efifb_set_system: fix miss valid address range in later BARs

[PATCH v2] x86:sysfb_efi:efifb_set_system: fix miss valid address range in later BARs

[Wang YanQing]

We can't just break out when meet start is equal to zero,
this will cause we miss valid address range in later BARs.

On the other hand, it isn't enough to test start only
for below situation:
0(start) <= lfb_base < end

Note: this patch also add a trivial optimization,
      break out after we find the address range
      is valid without test later BARs.

Signed-off-by: Wang YanQing <udknight@gmail.com>
---
 Due to the BUG this patch fix, I can't use video=efifb:
 boot parameter to get efifb on my new ThinkPad E550 for
 my old linux system hard disk with 3.10 kernel. In 3.10, 
 efifb is the only choice due to DRM/I915 in it doesn't 
 support the GPU.

 Changes:
 v1-v2:
 1: Do a trivial code optimization.

 arch/x86/kernel/sysfb_efi.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/sysfb_efi.c b/arch/x86/kernel/sysfb_efi.c
index b285d4e..5da924b 100644
--- a/arch/x86/kernel/sysfb_efi.c
+++ b/arch/x86/kernel/sysfb_efi.c
@@ -106,14 +106,24 @@ static int __init efifb_set_system(const struct dmi_system_id *id)
 					continue;
 				for (i = 0; i < DEVICE_COUNT_RESOURCE; i++) {
 					resource_size_t start, end;
+					unsigned long flags;
+
+					flags = pci_resource_flags(dev, i);
+					if (!(flags & IORESOURCE_MEM))
+						continue;
+
+					if (flags & IORESOURCE_UNSET)
+						continue;
+
+					if (pci_resource_len(dev, i) == 0)
+						continue;
 
 					start = pci_resource_start(dev, i);
-					if (start == 0)
-						break;
 					end = pci_resource_end(dev, i);
 					if (screen_info.lfb_base >= start &&
 					    screen_info.lfb_base < end) {
 						found_bar = 1;
+						break;
 					}
 				}
 			}
-- 
1.8.5.6.2.g3d8a54e.dirty

Re: [PATCH v2] x86:sysfb_efi:efifb_set_system: fix miss valid address range in later BARs

[Peter Jones]

On Sun, May 01, 2016 at 12:21:05AM +0800, Wang YanQing wrote:
> We can't just break out when meet start is equal to zero,
> this will cause we miss valid address range in later BARs.
> 
> On the other hand, it isn't enough to test start only
> for below situation:
> 0(start) <= lfb_base < end
> 
> Note: this patch also add a trivial optimization,
>       break out after we find the address range
>       is valid without test later BARs.
> 
> Signed-off-by: Wang YanQing <udknight@gmail.com>

This looks correct to me:

Reviewed-By: Peter Jones <pjones@redhat.com>

Cc'ing Matt Fleming, since this should probably go through the EFI tree.

> ---
>  Due to the BUG this patch fix, I can't use video=efifb:
>  boot parameter to get efifb on my new ThinkPad E550 for
>  my old linux system hard disk with 3.10 kernel. In 3.10, 
>  efifb is the only choice due to DRM/I915 in it doesn't 
>  support the GPU.
> 
>  Changes:
>  v1-v2:
>  1: Do a trivial code optimization.
> 
>  arch/x86/kernel/sysfb_efi.c | 14 ++++++++++++--
>  1 file changed, 12 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/x86/kernel/sysfb_efi.c b/arch/x86/kernel/sysfb_efi.c
> index b285d4e..5da924b 100644
> --- a/arch/x86/kernel/sysfb_efi.c
> +++ b/arch/x86/kernel/sysfb_efi.c
> @@ -106,14 +106,24 @@ static int __init efifb_set_system(const struct dmi_system_id *id)
>  					continue;
>  				for (i = 0; i < DEVICE_COUNT_RESOURCE; i++) {
>  					resource_size_t start, end;
> +					unsigned long flags;
> +
> +					flags = pci_resource_flags(dev, i);
> +					if (!(flags & IORESOURCE_MEM))
> +						continue;
> +
> +					if (flags & IORESOURCE_UNSET)
> +						continue;
> +
> +					if (pci_resource_len(dev, i) == 0)
> +						continue;
>  
>  					start = pci_resource_start(dev, i);
> -					if (start == 0)
> -						break;
>  					end = pci_resource_end(dev, i);
>  					if (screen_info.lfb_base >= start &&
>  					    screen_info.lfb_base < end) {
>  						found_bar = 1;
> +						break;
>  					}
>  				}
>  			}
> -- 
> 1.8.5.6.2.g3d8a54e.dirty

-- 
  Peter

Re: [PATCH v2] x86:sysfb_efi:efifb_set_system: fix miss valid address range in later BARs

[Matt Fleming]

On Mon, 02 May, at 03:11:20PM, Peter Jones wrote:
> On Sun, May 01, 2016 at 12:21:05AM +0800, Wang YanQing wrote:
> > We can't just break out when meet start is equal to zero,
> > this will cause we miss valid address range in later BARs.
> > 
> > On the other hand, it isn't enough to test start only
> > for below situation:
> > 0(start) <= lfb_base < end
> > 
> > Note: this patch also add a trivial optimization,
> >       break out after we find the address range
> >       is valid without test later BARs.
> > 
> > Signed-off-by: Wang YanQing <udknight@gmail.com>
> 
> This looks correct to me:
> 
> Reviewed-By: Peter Jones <pjones@redhat.com>
> 
> Cc'ing Matt Fleming, since this should probably go through the EFI tree.

Applied, thanks.