lkml.org 
[lkml]   [2022]   [Feb]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v9 05/11] PCI/VGA: Move firmware default device detection to ADD_DEVICE path
Date
From: Huacai Chen <chenhuacai@loongson.cn>

Previously we selected the firmware default device, i.e., one that owns the
boot framebuffer, as the default device in vga_arb_select_default_device().
This was only done in the vga_arb_device_init() subsys_initcall, so devices
enumerated later, e.g., by pcibios_init(), were not eligible.

Fix this by moving the firmware default device selection from
vga_arb_select_default_device() to vga_arbiter_add_pci_device(), which is
called after every PCI device is enumerated, either by the
vga_arb_device_init() subsys_initcall or as an ADD_DEVICE notifier.

Note that if vga_arb_select_default_device() previously found a device
owning the boot framebuffer, it unconditionally set it to be the default
VGA device, and no subsequent device could replace it.

[bhelgaas: commit log, restructure slightly]
Link: https://lore.kernel.org/r/20211015061512.2941859-7-chenhuacai@loongson.cn
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Cc: Bruno Prémont <bonbons@linux-vserver.org>
---
drivers/pci/vgaarb.c | 37 +++++++++++++++++--------------------
1 file changed, 17 insertions(+), 20 deletions(-)

diff --git a/drivers/pci/vgaarb.c b/drivers/pci/vgaarb.c
index 58e0a12e623b..c3323ab4f98e 100644
--- a/drivers/pci/vgaarb.c
+++ b/drivers/pci/vgaarb.c
@@ -72,6 +72,7 @@ struct vga_device {
unsigned int io_norm_cnt; /* normal IO count */
unsigned int mem_norm_cnt; /* normal MEM count */
bool bridge_has_one_vga;
+ bool is_firmware_default; /* device selected by firmware */
unsigned int (*set_decode)(struct pci_dev *pdev, bool decode);
};

@@ -565,10 +566,9 @@ void vga_put(struct pci_dev *pdev, unsigned int rsrc)
}
EXPORT_SYMBOL(vga_put);

-static void __init vga_select_framebuffer_device(struct pci_dev *pdev)
+static bool vga_is_firmware_default(struct pci_dev *pdev)
{
#if defined(CONFIG_X86) || defined(CONFIG_IA64)
- struct device *dev = &pdev->dev;
u64 base = screen_info.lfb_base;
u64 size = screen_info.lfb_size;
u64 limit;
@@ -583,15 +583,6 @@ static void __init vga_select_framebuffer_device(struct pci_dev *pdev)

limit = base + size;

- /*
- * Override vga_arbiter_add_pci_device()'s I/O based detection
- * as it may take the wrong device (e.g. on Apple system under
- * EFI).
- *
- * Select the device owning the boot framebuffer if there is
- * one.
- */
-
/* Does firmware framebuffer belong to us? */
for (i = 0; i < DEVICE_COUNT_RESOURCE; i++) {
flags = pci_resource_flags(pdev, i);
@@ -608,13 +599,10 @@ static void __init vga_select_framebuffer_device(struct pci_dev *pdev)
if (base < start || limit >= end)
continue;

- if (!vga_default_device())
- vgaarb_info(dev, "setting as boot device\n");
- else if (pdev != vga_default_device())
- vgaarb_info(dev, "overriding boot device\n");
- vga_set_default_device(pdev);
+ return true;
}
#endif
+ return false;
}

static bool vga_arb_integrated_gpu(struct device *dev)
@@ -635,6 +623,7 @@ static bool vga_arb_integrated_gpu(struct device *dev)
static bool vga_is_boot_device(struct vga_device *vgadev)
{
struct vga_device *boot_vga = vgadev_find(vga_default_device());
+ struct pci_dev *pdev = vgadev->pdev;

/*
* We select the default VGA device in this order:
@@ -645,6 +634,18 @@ static bool vga_is_boot_device(struct vga_device *vgadev)
* Other device (see vga_arb_select_default_device())
*/

+ /*
+ * We always prefer a firmware default device, so if we've already
+ * found one, there's no need to consider vgadev.
+ */
+ if (boot_vga && boot_vga->is_firmware_default)
+ return false;
+
+ if (vga_is_firmware_default(pdev)) {
+ vgadev->is_firmware_default = true;
+ return true;
+ }
+
/*
* A legacy VGA device has MEM and IO enabled and any bridges
* leading to it have PCI_BRIDGE_CTL_VGA enabled so the legacy
@@ -1531,10 +1532,6 @@ static void __init vga_arb_select_default_device(void)
struct pci_dev *pdev, *found = NULL;
struct vga_device *vgadev;

- list_for_each_entry(vgadev, &vga_list, list) {
- vga_select_framebuffer_device(vgadev->pdev);
- }
-
if (!vga_default_device()) {
list_for_each_entry_reverse(vgadev, &vga_list, list) {
struct device *dev = &vgadev->pdev->dev;
--
2.25.1
\
 
 \ /
  Last update: 2022-02-24 23:49    [W:0.128 / U:3.292 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site