Hi, Bjorn,
On Thu, Sep 16, 2021 at 4:39 PM Huacai Chen chenhuacai@loongson.cn wrote:
From: Bjorn Helgaas bhelgaas@google.com
The VGA arbiter is really PCI-specific and doesn't depend on any GPU things. Move it to the PCI subsystem.
I found a new problem, after moving vgaarb.c to drivers/pci, misc_register() in vga_arb_device_init() fails with -ENODEV, the root cause is still initcall order. Both vga_arb_device_init() and misc_init() are subsys_initcall(), and drivers/Makefile looks like this: obj-y += pci/ ...... obj-y += char/ ...... obj-y += gpu/
So vga_arb_device_init() in the pci directory runs before misc_init() in the char directory, and misc_register() fails.
There are two methods to resolve: 1, keep vgaarb.c in drivers/gpu; 2, make vga_arb_device_init() to be subsys_initcall_sync(). I prefer the first one, but it seems you don't like both of them.
Huacai
Signed-off-by: Bjorn Helgaas bhelgaas@google.com Signed-off-by: Huacai Chen chenhuacai@loongson.cn
drivers/gpu/vga/Kconfig | 19 ------------------- drivers/gpu/vga/Makefile | 1 - drivers/pci/Kconfig | 19 +++++++++++++++++++ drivers/pci/Makefile | 1 + drivers/{gpu/vga => pci}/vgaarb.c | 0 5 files changed, 20 insertions(+), 20 deletions(-) rename drivers/{gpu/vga => pci}/vgaarb.c (100%)
diff --git a/drivers/gpu/vga/Kconfig b/drivers/gpu/vga/Kconfig index 1ad4c4ef0b5e..eb8b14ab22c3 100644 --- a/drivers/gpu/vga/Kconfig +++ b/drivers/gpu/vga/Kconfig @@ -1,23 +1,4 @@ # SPDX-License-Identifier: GPL-2.0-only -config VGA_ARB
bool "VGA Arbitration" if EXPERTdefault ydepends on (PCI && !S390)helpSome "legacy" VGA devices implemented on PCI typically have the samehard-decoded addresses as they did on ISA. When multiple PCI devicesare accessed at same time they need some kind of coordination. Pleasesee Documentation/gpu/vgaarbiter.rst for more details. Select this toenable VGA arbiter.-config VGA_ARB_MAX_GPUS
int "Maximum number of GPUs"default 16depends on VGA_ARBhelpReserves space in the kernel to maintain resource locking formultiple GPUS. The overhead for each GPU is very small.config VGA_SWITCHEROO bool "Laptop Hybrid Graphics - GPU switching support" depends on X86 diff --git a/drivers/gpu/vga/Makefile b/drivers/gpu/vga/Makefile index e92064442d60..9800620deda3 100644 --- a/drivers/gpu/vga/Makefile +++ b/drivers/gpu/vga/Makefile @@ -1,3 +1,2 @@ # SPDX-License-Identifier: GPL-2.0-only -obj-$(CONFIG_VGA_ARB) += vgaarb.o obj-$(CONFIG_VGA_SWITCHEROO) += vga_switcheroo.o diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig index 0c473d75e625..7c9e56d7b857 100644 --- a/drivers/pci/Kconfig +++ b/drivers/pci/Kconfig @@ -252,6 +252,25 @@ config PCIE_BUS_PEER2PEER
endchoice
+config VGA_ARB
bool "VGA Arbitration" if EXPERTdefault ydepends on (PCI && !S390)helpSome "legacy" VGA devices implemented on PCI typically have the samehard-decoded addresses as they did on ISA. When multiple PCI devicesare accessed at same time they need some kind of coordination. Pleasesee Documentation/gpu/vgaarbiter.rst for more details. Select this toenable VGA arbiter.+config VGA_ARB_MAX_GPUS
int "Maximum number of GPUs"default 16depends on VGA_ARBhelpReserves space in the kernel to maintain resource locking formultiple GPUS. The overhead for each GPU is very small.source "drivers/pci/hotplug/Kconfig" source "drivers/pci/controller/Kconfig" source "drivers/pci/endpoint/Kconfig" diff --git a/drivers/pci/Makefile b/drivers/pci/Makefile index d62c4ac4ae1b..ebe720f69b15 100644 --- a/drivers/pci/Makefile +++ b/drivers/pci/Makefile @@ -29,6 +29,7 @@ obj-$(CONFIG_PCI_PF_STUB) += pci-pf-stub.o obj-$(CONFIG_PCI_ECAM) += ecam.o obj-$(CONFIG_PCI_P2PDMA) += p2pdma.o obj-$(CONFIG_XEN_PCIDEV_FRONTEND) += xen-pcifront.o +obj-$(CONFIG_VGA_ARB) += vgaarb.o
# Endpoint library must be initialized before its users obj-$(CONFIG_PCI_ENDPOINT) += endpoint/ diff --git a/drivers/gpu/vga/vgaarb.c b/drivers/pci/vgaarb.c similarity index 100% rename from drivers/gpu/vga/vgaarb.c rename to drivers/pci/vgaarb.c -- 2.27.0