From: Shixiong Ou <[email protected]>
[WHY]
On an ARM machine, the following log is present:
[ 0.900884] efifb: framebuffer at 0x1020000000, using 3072k, total 3072k
[ 2.297884] amdgpu 0000:04:00.0: remove_conflicting_pci_framebuffers: bar 0:
0x1000000000 -> 0x100fffffff
[ 2.297886] amdgpu 0000:04:00.0: remove_conflicting_pci_framebuffers: bar 2:
0x1010000000 -> 0x10101fffff
[ 2.297888] amdgpu 0000:04:00.0: remove_conflicting_pci_framebuffers: bar 5:
0x58200000 -> 0x5823ffff
It show that the efifb framebuffer base is out of PCI BAR, and this
results in both efi-framebuffer and amdgpudrmfb co-existing.
The fbcon will be bound to efi-framebuffer by default and cannot be used.
[HOW]
Do not load efifb driver if PCI BAR has changed but not fixuped.
In the following cases:
1. screen_info_lfb_pdev is NULL.
2. __screen_info_relocation_is_valid return false.
Signed-off-by: Shixiong Ou <[email protected]>
---
drivers/video/fbdev/efifb.c | 4 ++++
drivers/video/screen_info_pci.c | 24 ++++++++++++++++++++++++
include/linux/screen_info.h | 5 +++++
3 files changed, 33 insertions(+)
diff --git a/drivers/video/fbdev/efifb.c b/drivers/video/fbdev/efifb.c
index 0e1bd3dba255..de8d016c9a66 100644
--- a/drivers/video/fbdev/efifb.c
+++ b/drivers/video/fbdev/efifb.c
@@ -303,6 +303,10 @@ static void efifb_setup(struct screen_info *si, char
*options)
static inline bool fb_base_is_valid(struct screen_info *si)
{
+ /* check whether fb_base has changed but not fixuped */
+ if (!screen_info_is_useful())
+ return false;
+
if (si->lfb_base)
return true;
diff --git a/drivers/video/screen_info_pci.c b/drivers/video/screen_info_pci.c
index 66bfc1d0a6dc..ac57dcaf0cac 100644
--- a/drivers/video/screen_info_pci.c
+++ b/drivers/video/screen_info_pci.c
@@ -9,6 +9,8 @@ static struct pci_dev *screen_info_lfb_pdev;
static size_t screen_info_lfb_bar;
static resource_size_t screen_info_lfb_res_start; // original start of resource
static resource_size_t screen_info_lfb_offset; // framebuffer offset within
resource
+static bool screen_info_changed;
+static bool screen_info_fixuped;
static bool __screen_info_relocation_is_valid(const struct screen_info *si,
struct resource *pr)
{
@@ -24,6 +26,24 @@ static bool __screen_info_relocation_is_valid(const struct
screen_info *si, stru
return true;
}
+bool screen_info_is_useful(void)
+{
+ unsigned int type;
+ const struct screen_info *si = &screen_info;
+
+ type = screen_info_video_type(si);
+ if (type != VIDEO_TYPE_EFI)
+ return true;
+
+ if (screen_info_changed && !screen_info_fixuped) {
+ pr_warn("The screen_info has changed but not fixuped");
+ return false;
+ }
+
+ pr_info("The screen_info is useful");
+ return true;
+}
+
void screen_info_apply_fixups(void)
{
struct screen_info *si = &screen_info;
@@ -32,18 +52,22 @@ void screen_info_apply_fixups(void)
struct resource *pr =
&screen_info_lfb_pdev->resource[screen_info_lfb_bar];
if (pr->start != screen_info_lfb_res_start) {
+ screen_info_changed = true;
if (__screen_info_relocation_is_valid(si, pr)) {
/*
* Only update base if we have an actual
* relocation to a valid I/O range.
*/
__screen_info_set_lfb_base(si, pr->start +
screen_info_lfb_offset);
+ screen_info_fixuped = true;
pr_info("Relocating firmware framebuffer to
offset %pa[d] within %pr\n",
&screen_info_lfb_offset, pr);
} else {
pr_warn("Invalid relocating, disabling firmware
framebuffer\n");
}
}
+ } else {
+ screen_info_changed = true;
}
}
diff --git a/include/linux/screen_info.h b/include/linux/screen_info.h
index 923d68e07679..632cdbb1adbe 100644
--- a/include/linux/screen_info.h
+++ b/include/linux/screen_info.h
@@ -138,9 +138,14 @@ ssize_t screen_info_resources(const struct screen_info
*si, struct resource *r,
u32 __screen_info_lfb_bits_per_pixel(const struct screen_info *si);
#if defined(CONFIG_PCI)
+bool screen_info_is_useful(void);
void screen_info_apply_fixups(void);
struct pci_dev *screen_info_pci_dev(const struct screen_info *si);
#else
+bool screen_info_is_useful(void)
+{
+ return true;
+}
static inline void screen_info_apply_fixups(void)
{ }
static inline struct pci_dev *screen_info_pci_dev(const struct screen_info *si)
--
2.25.1
