My original work is at [1].
Bjorn do some rework and extension in V2. It moves the VGA arbiter to the PCI subsystem, fixes a few nits, and breaks a few pieces to make the main patch a little smaller.
V3 rewrite the commit log of the last patch (which is also summarized by Bjorn).
All comments welcome!
[1] https://lore.kernel.org/dri-devel/20210705100503.1120643-1-chenhuacai@loongs...
Bjorn Helgaas (4): PCI/VGA: Move vgaarb to drivers/pci PCI/VGA: Replace full MIT license text with SPDX identifier PCI/VGA: Use unsigned format string to print lock counts PCI/VGA: Remove empty vga_arb_device_card_gone()
Huacai Chen (5): PCI/VGA: Move vga_arb_integrated_gpu() earlier in file PCI/VGA: Prefer vga_default_device() PCI/VGA: Split out vga_arb_update_default_device() PCI/VGA: Log bridge control messages when adding devices PCI/VGA: Rework default VGA device selection
Signed-off-by: Huacai Chen chenhuacai@loongson.cn Signed-off-by: Bjorn Helgaas bhelgaas@google.com --- drivers/gpu/vga/Kconfig | 19 --- drivers/gpu/vga/Makefile | 1 - drivers/pci/Kconfig | 19 +++ drivers/pci/Makefile | 1 + drivers/{gpu/vga => pci}/vgaarb.c | 269 ++++++++++++------------------ 5 files changed, 126 insertions(+), 183 deletions(-) rename drivers/{gpu/vga => pci}/vgaarb.c (90%) -- 2.27.0
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.
Signed-off-by: Bjorn Helgaas bhelgaas@google.com --- 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 EXPERT - default y - depends on (PCI && !S390) - help - Some "legacy" VGA devices implemented on PCI typically have the same - hard-decoded addresses as they did on ISA. When multiple PCI devices - are accessed at same time they need some kind of coordination. Please - see Documentation/gpu/vgaarbiter.rst for more details. Select this to - enable VGA arbiter. - -config VGA_ARB_MAX_GPUS - int "Maximum number of GPUs" - default 16 - depends on VGA_ARB - help - Reserves space in the kernel to maintain resource locking for - multiple 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 EXPERT + default y + depends on (PCI && !S390) + help + Some "legacy" VGA devices implemented on PCI typically have the same + hard-decoded addresses as they did on ISA. When multiple PCI devices + are accessed at same time they need some kind of coordination. Please + see Documentation/gpu/vgaarbiter.rst for more details. Select this to + enable VGA arbiter. + +config VGA_ARB_MAX_GPUS + int "Maximum number of GPUs" + default 16 + depends on VGA_ARB + help + Reserves space in the kernel to maintain resource locking for + multiple 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
From: Bjorn Helgaas bhelgaas@google.com
Per Documentation/process/license-rules.rst, the SPDX MIT identifier is equivalent to including the entire MIT license text from LICENSES/preferred/MIT.
Replace the MIT license text with the equivalent SPDX identifier.
Signed-off-by: Bjorn Helgaas bhelgaas@google.com --- drivers/pci/vgaarb.c | 23 +---------------------- 1 file changed, 1 insertion(+), 22 deletions(-)
diff --git a/drivers/pci/vgaarb.c b/drivers/pci/vgaarb.c index 949fde433ea2..61b57abcb014 100644 --- a/drivers/pci/vgaarb.c +++ b/drivers/pci/vgaarb.c @@ -1,32 +1,11 @@ +// SPDX-License-Identifier: MIT /* * vgaarb.c: Implements the VGA arbitration. For details refer to * Documentation/gpu/vgaarbiter.rst * - * * (C) Copyright 2005 Benjamin Herrenschmidt benh@kernel.crashing.org * (C) Copyright 2007 Paulo R. Zanoni przanoni@gmail.com * (C) Copyright 2007, 2009 Tiago Vignatti vignatti@freedesktop.org - * - * Permission is hereby granted, free of charge, to any person obtaining a - * copy of this software and associated documentation files (the "Software"), - * to deal in the Software without restriction, including without limitation - * the rights to use, copy, modify, merge, publish, distribute, sublicense, - * and/or sell copies of the Software, and to permit persons to whom the - * Software is furnished to do so, subject to the following conditions: - * - * The above copyright notice and this permission notice (including the next - * paragraph) shall be included in all copies or substantial portions of the - * Software. - * - * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR - * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, - * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL - * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER - * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING - * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER - * DEALINGS - * IN THE SOFTWARE. - * */
#define pr_fmt(fmt) "vgaarb: " fmt
From: Bjorn Helgaas bhelgaas@google.com
In struct vga_device, io_lock_cnt and mem_lock_cnt are unsigned, but we previously printed them with "%d", the signed decimal format. Print them with the unsigned format "%u" instead.
Signed-off-by: Bjorn Helgaas bhelgaas@google.com --- drivers/pci/vgaarb.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/pci/vgaarb.c b/drivers/pci/vgaarb.c index 61b57abcb014..e4153ab70481 100644 --- a/drivers/pci/vgaarb.c +++ b/drivers/pci/vgaarb.c @@ -1022,7 +1022,7 @@ static ssize_t vga_arb_read(struct file *file, char __user *buf,
/* Fill the buffer with infos */ len = snprintf(lbuf, 1024, - "count:%d,PCI:%s,decodes=%s,owns=%s,locks=%s(%d:%d)\n", + "count:%d,PCI:%s,decodes=%s,owns=%s,locks=%s(%u:%u)\n", vga_decode_count, pci_name(pdev), vga_iostate_to_str(vgadev->decodes), vga_iostate_to_str(vgadev->owns),
From: Bjorn Helgaas bhelgaas@google.com
vga_arb_device_card_gone() has always been empty. Remove it.
Signed-off-by: Bjorn Helgaas bhelgaas@google.com --- drivers/pci/vgaarb.c | 16 +--------------- 1 file changed, 1 insertion(+), 15 deletions(-)
diff --git a/drivers/pci/vgaarb.c b/drivers/pci/vgaarb.c index e4153ab70481..c984c76b3fd7 100644 --- a/drivers/pci/vgaarb.c +++ b/drivers/pci/vgaarb.c @@ -104,8 +104,6 @@ static int vga_str_to_iostate(char *buf, int str_size, int *io_state) /* this is only used a cookie - it should not be dereferenced */ static struct pci_dev *vga_default;
-static void vga_arb_device_card_gone(struct pci_dev *pdev); - /* Find somebody in our list */ static struct vga_device *vgadev_find(struct pci_dev *pdev) { @@ -741,10 +739,6 @@ static bool vga_arbiter_del_pci_device(struct pci_dev *pdev) /* Remove entry from list */ list_del(&vgadev->list); vga_count--; - /* Notify userland driver that the device is gone so it discards - * it's copies of the pci_dev pointer - */ - vga_arb_device_card_gone(pdev);
/* Wake up all possible waiters */ wake_up_all(&vga_wait_queue); @@ -994,9 +988,7 @@ static ssize_t vga_arb_read(struct file *file, char __user *buf, if (lbuf == NULL) return -ENOMEM;
- /* Shields against vga_arb_device_card_gone (pci_dev going - * away), and allows access to vga list - */ + /* Protects vga_list */ spin_lock_irqsave(&vga_lock, flags);
/* If we are targeting the default, use it */ @@ -1013,8 +1005,6 @@ static ssize_t vga_arb_read(struct file *file, char __user *buf, /* Wow, it's not in the list, that shouldn't happen, * let's fix us up and return invalid card */ - if (pdev == priv->target) - vga_arb_device_card_gone(pdev); spin_unlock_irqrestore(&vga_lock, flags); len = sprintf(lbuf, "invalid"); goto done; @@ -1358,10 +1348,6 @@ static int vga_arb_release(struct inode *inode, struct file *file) return 0; }
-static void vga_arb_device_card_gone(struct pci_dev *pdev) -{ -} - /* * callback any registered clients to let them know we have a * change in VGA cards
Move vga_arb_integrated_gpu() earlier in file to prepare for future patch. No functional change intended.
[bhelgaas: split to separate patch] Signed-off-by: Huacai Chen chenhuacai@loongson.cn Signed-off-by: Bjorn Helgaas bhelgaas@google.com --- drivers/pci/vgaarb.c | 28 ++++++++++++++-------------- 1 file changed, 14 insertions(+), 14 deletions(-)
diff --git a/drivers/pci/vgaarb.c b/drivers/pci/vgaarb.c index c984c76b3fd7..1f8fb37be5fa 100644 --- a/drivers/pci/vgaarb.c +++ b/drivers/pci/vgaarb.c @@ -563,6 +563,20 @@ void vga_put(struct pci_dev *pdev, unsigned int rsrc) } EXPORT_SYMBOL(vga_put);
+#if defined(CONFIG_ACPI) +static bool vga_arb_integrated_gpu(struct device *dev) +{ + struct acpi_device *adev = ACPI_COMPANION(dev); + + return adev && !strcmp(acpi_device_hid(adev), ACPI_VIDEO_HID); +} +#else +static bool vga_arb_integrated_gpu(struct device *dev) +{ + return false; +} +#endif + /* * Rules for using a bridge to control a VGA descendant decoding: if a bridge * has only one VGA descendant then it can be used to control the VGA routing @@ -1416,20 +1430,6 @@ static struct miscdevice vga_arb_device = { MISC_DYNAMIC_MINOR, "vga_arbiter", &vga_arb_device_fops };
-#if defined(CONFIG_ACPI) -static bool vga_arb_integrated_gpu(struct device *dev) -{ - struct acpi_device *adev = ACPI_COMPANION(dev); - - return adev && !strcmp(acpi_device_hid(adev), ACPI_VIDEO_HID); -} -#else -static bool vga_arb_integrated_gpu(struct device *dev) -{ - return false; -} -#endif - static void __init vga_arb_select_default_device(void) { struct pci_dev *pdev, *found = NULL;
Use the vga_default_device() interface consistently instead of directly testing vga_default. No functional change intended.
[bhelgaas: split to separate patch and extended] Signed-off-by: Huacai Chen chenhuacai@loongson.cn Signed-off-by: Bjorn Helgaas bhelgaas@google.com --- drivers/pci/vgaarb.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/pci/vgaarb.c b/drivers/pci/vgaarb.c index 1f8fb37be5fa..a6a5864ff538 100644 --- a/drivers/pci/vgaarb.c +++ b/drivers/pci/vgaarb.c @@ -173,7 +173,7 @@ int vga_remove_vgacon(struct pci_dev *pdev) { int ret = 0;
- if (pdev != vga_default) + if (pdev != vga_default_device()) return 0; vgaarb_info(&pdev->dev, "deactivate vga console\n");
@@ -707,7 +707,7 @@ static bool vga_arbiter_add_pci_device(struct pci_dev *pdev) /* Deal with VGA default device. Use first enabled one * by default if arch doesn't have it's own hook */ - if (vga_default == NULL && + if (!vga_default_device() && ((vgadev->owns & VGA_RSRC_LEGACY_MASK) == VGA_RSRC_LEGACY_MASK)) { vgaarb_info(&pdev->dev, "setting as boot VGA device\n"); vga_set_default_device(pdev); @@ -744,7 +744,7 @@ static bool vga_arbiter_del_pci_device(struct pci_dev *pdev) goto bail; }
- if (vga_default == pdev) + if (vga_default_device() == pdev) vga_set_default_device(NULL);
if (vgadev->decodes & (VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM))
If there's no default VGA device, and we find a VGA device that owns the legacy VGA resources, we make that device the default. Split this logic out from vga_arbiter_add_pci_device() into a new function, vga_arb_update_default_device().
[bhelgaas: split another piece to separate patch] Signed-off-by: Huacai Chen chenhuacai@loongson.cn Signed-off-by: Bjorn Helgaas bhelgaas@google.com --- drivers/pci/vgaarb.c | 25 ++++++++++++++++--------- 1 file changed, 16 insertions(+), 9 deletions(-)
diff --git a/drivers/pci/vgaarb.c b/drivers/pci/vgaarb.c index a6a5864ff538..4cecb599f5ed 100644 --- a/drivers/pci/vgaarb.c +++ b/drivers/pci/vgaarb.c @@ -577,6 +577,21 @@ static bool vga_arb_integrated_gpu(struct device *dev) } #endif
+static void vga_arb_update_default_device(struct vga_device *vgadev) +{ + struct pci_dev *pdev = vgadev->pdev; + + /* + * If we don't have a default VGA device yet, and this device owns + * the legacy VGA resources, make it the default. + */ + if (!vga_default_device() && + ((vgadev->owns & VGA_RSRC_LEGACY_MASK) == VGA_RSRC_LEGACY_MASK)) { + vgaarb_info(&pdev->dev, "setting as boot VGA device\n"); + vga_set_default_device(pdev); + } +} + /* * Rules for using a bridge to control a VGA descendant decoding: if a bridge * has only one VGA descendant then it can be used to control the VGA routing @@ -704,15 +719,7 @@ static bool vga_arbiter_add_pci_device(struct pci_dev *pdev) bus = bus->parent; }
- /* Deal with VGA default device. Use first enabled one - * by default if arch doesn't have it's own hook - */ - if (!vga_default_device() && - ((vgadev->owns & VGA_RSRC_LEGACY_MASK) == VGA_RSRC_LEGACY_MASK)) { - vgaarb_info(&pdev->dev, "setting as boot VGA device\n"); - vga_set_default_device(pdev); - } - + vga_arb_update_default_device(vgadev); vga_arbiter_check_bridge_sharing(vgadev);
/* Add to the list */
Previously vga_arb_device_init() iterated through all VGA devices and indicated whether legacy VGA routing to each could be controlled by an upstream bridge.
But we determine that information in vga_arbiter_add_pci_device(), which we call for every device, so we can log it there without iterating through the VGA devices again.
Note that we call vga_arbiter_check_bridge_sharing() before adding the device to vga_list, so we have to handle the very first device separately.
[bhelgaas: commit log, split another piece to separate patch, fix list_empty() issue] Link: https://lore.kernel.org/r/20210705100503.1120643-1-chenhuacai@loongson.cn Signed-off-by: Huacai Chen chenhuacai@loongson.cn Signed-off-by: Bjorn Helgaas bhelgaas@google.com --- drivers/pci/vgaarb.c | 19 ++++++++----------- 1 file changed, 8 insertions(+), 11 deletions(-)
diff --git a/drivers/pci/vgaarb.c b/drivers/pci/vgaarb.c index 4cecb599f5ed..dd07b1c3205f 100644 --- a/drivers/pci/vgaarb.c +++ b/drivers/pci/vgaarb.c @@ -609,8 +609,10 @@ static void vga_arbiter_check_bridge_sharing(struct vga_device *vgadev)
vgadev->bridge_has_one_vga = true;
- if (list_empty(&vga_list)) + if (list_empty(&vga_list)) { + vgaarb_info(&vgadev->pdev->dev, "bridge control possible\n"); return; + }
/* okay iterate the new devices bridge hierarachy */ new_bus = vgadev->pdev->bus; @@ -649,6 +651,11 @@ static void vga_arbiter_check_bridge_sharing(struct vga_device *vgadev) } new_bus = new_bus->parent; } + + if (vgadev->bridge_has_one_vga) + vgaarb_info(&vgadev->pdev->dev, "bridge control possible\n"); + else + vgaarb_info(&vgadev->pdev->dev, "no bridge control possible\n"); }
/* @@ -1527,7 +1534,6 @@ static int __init vga_arb_device_init(void) { int rc; struct pci_dev *pdev; - struct vga_device *vgadev;
rc = misc_register(&vga_arb_device); if (rc < 0) @@ -1543,15 +1549,6 @@ static int __init vga_arb_device_init(void) PCI_ANY_ID, pdev)) != NULL) vga_arbiter_add_pci_device(pdev);
- list_for_each_entry(vgadev, &vga_list, list) { - struct device *dev = &vgadev->pdev->dev; - - if (vgadev->bridge_has_one_vga) - vgaarb_info(dev, "bridge control possible\n"); - else - vgaarb_info(dev, "no bridge control possible\n"); - } - vga_arb_select_default_device();
pr_info("loaded\n");
Current default VGA device selection fails in some cases:
- On BMC system, the AST2500 bridge [1a03:1150] does not implement PCI_BRIDGE_CTL_VGA [1]. This is perfectly legal but means the legacy VGA resources won't reach downstream devices unless they're included in the usual bridge windows.
- vga_arb_select_default_device() will set a device below such a bridge as the default VGA device as long as it has PCI_COMMAND_IO and PCI_COMMAND_MEMORY enabled.
- vga_arbiter_add_pci_device() is called for every VGA device, either at boot-time or at hot-add time, and it will also set the device as the default VGA device, but ONLY if all bridges leading to it implement PCI_BRIDGE_CTL_VGA.
- This difference between vga_arb_select_default_device() and vga_arbiter_add_pci_device() means that a device below an AST2500 or similar bridge can only be set as the default if it is enumerated before vga_arb_device_init().
- On ACPI-based systems, PCI devices are enumerated by acpi_init(), which runs before vga_arb_device_init().
- On non-ACPI systems, like on MIPS system, they are enumerated by pcibios_init(), which typically runs *after* vga_arb_device_init().
So I made vga_arb_update_default_device() to replace the current vga_ arb_select_default_device(), which will be call from vga_arbiter_add_ pci_device(), set the default device even if it does not own the VGA resources because an upstream bridge doesn't implement PCI_BRIDGE_CTL_ VGA. And the default VGA device is updated if a better one is found (device with legacy resources enabled is better, device owns the firmware framebuffer is even better). --- drivers/pci/vgaarb.c | 158 ++++++++++++++++++------------------------- 1 file changed, 66 insertions(+), 92 deletions(-)
diff --git a/drivers/pci/vgaarb.c b/drivers/pci/vgaarb.c index dd07b1c3205f..0b059a2fc749 100644 --- a/drivers/pci/vgaarb.c +++ b/drivers/pci/vgaarb.c @@ -580,16 +580,79 @@ static bool vga_arb_integrated_gpu(struct device *dev) static void vga_arb_update_default_device(struct vga_device *vgadev) { struct pci_dev *pdev = vgadev->pdev; + struct device *dev = &pdev->dev; + struct vga_device *vgadev_default; +#if defined(CONFIG_X86) || defined(CONFIG_IA64) + int i; + unsigned long flags; + u64 base = screen_info.lfb_base; + u64 size = screen_info.lfb_size; + u64 limit; + resource_size_t start, end; +#endif
/* * If we don't have a default VGA device yet, and this device owns * the legacy VGA resources, make it the default. */ - if (!vga_default_device() && - ((vgadev->owns & VGA_RSRC_LEGACY_MASK) == VGA_RSRC_LEGACY_MASK)) { - vgaarb_info(&pdev->dev, "setting as boot VGA device\n"); + if (!vga_default_device()) { + if ((vgadev->owns & VGA_RSRC_LEGACY_MASK) == VGA_RSRC_LEGACY_MASK) + vgaarb_info(dev, "setting as boot VGA device\n"); + else + vgaarb_info(dev, "setting as boot device (VGA legacy resources not available)\n"); vga_set_default_device(pdev); } + + vgadev_default = vgadev_find(vga_default); + + /* Overridden by a better device */ + if (vgadev_default && ((vgadev_default->owns & VGA_RSRC_LEGACY_MASK) == 0) + && ((vgadev->owns & VGA_RSRC_LEGACY_MASK) == VGA_RSRC_LEGACY_MASK)) { + vgaarb_info(dev, "overriding boot VGA device\n"); + vga_set_default_device(pdev); + } + + if (vga_arb_integrated_gpu(dev)) { + vgaarb_info(dev, "overriding boot VGA device\n"); + vga_set_default_device(pdev); + } + +#if defined(CONFIG_X86) || defined(CONFIG_IA64) + if (screen_info.capabilities & VIDEO_CAPABILITY_64BIT_BASE) + base |= (u64)screen_info.ext_lfb_base << 32; + + 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(vgadev->pdev, i); + + if ((flags & IORESOURCE_MEM) == 0) + continue; + + start = pci_resource_start(vgadev->pdev, i); + end = pci_resource_end(vgadev->pdev, i); + + if (!start || !end) + continue; + + if (base < start || limit >= end) + continue; + + if (vgadev->pdev != vga_default_device()) + vgaarb_info(dev, "overriding boot device\n"); + vga_set_default_device(vgadev->pdev); + } +#endif }
/* @@ -1444,92 +1507,6 @@ static struct miscdevice vga_arb_device = { MISC_DYNAMIC_MINOR, "vga_arbiter", &vga_arb_device_fops };
-static void __init vga_arb_select_default_device(void) -{ - struct pci_dev *pdev, *found = NULL; - struct vga_device *vgadev; - -#if defined(CONFIG_X86) || defined(CONFIG_IA64) - u64 base = screen_info.lfb_base; - u64 size = screen_info.lfb_size; - u64 limit; - resource_size_t start, end; - unsigned long flags; - int i; - - if (screen_info.capabilities & VIDEO_CAPABILITY_64BIT_BASE) - base |= (u64)screen_info.ext_lfb_base << 32; - - limit = base + size; - - list_for_each_entry(vgadev, &vga_list, list) { - struct device *dev = &vgadev->pdev->dev; - /* - * 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(vgadev->pdev, i); - - if ((flags & IORESOURCE_MEM) == 0) - continue; - - start = pci_resource_start(vgadev->pdev, i); - end = pci_resource_end(vgadev->pdev, i); - - if (!start || !end) - continue; - - if (base < start || limit >= end) - continue; - - if (!vga_default_device()) - vgaarb_info(dev, "setting as boot device\n"); - else if (vgadev->pdev != vga_default_device()) - vgaarb_info(dev, "overriding boot device\n"); - vga_set_default_device(vgadev->pdev); - } - } -#endif - - if (!vga_default_device()) { - list_for_each_entry_reverse(vgadev, &vga_list, list) { - struct device *dev = &vgadev->pdev->dev; - u16 cmd; - - pdev = vgadev->pdev; - pci_read_config_word(pdev, PCI_COMMAND, &cmd); - if (cmd & (PCI_COMMAND_IO | PCI_COMMAND_MEMORY)) { - found = pdev; - if (vga_arb_integrated_gpu(dev)) - break; - } - } - } - - if (found) { - vgaarb_info(&found->dev, "setting as boot device (VGA legacy resources not available)\n"); - vga_set_default_device(found); - return; - } - - if (!vga_default_device()) { - vgadev = list_first_entry_or_null(&vga_list, - struct vga_device, list); - if (vgadev) { - struct device *dev = &vgadev->pdev->dev; - vgaarb_info(dev, "setting as boot device (VGA legacy resources not available)\n"); - vga_set_default_device(vgadev->pdev); - } - } -} - static int __init vga_arb_device_init(void) { int rc; @@ -1549,9 +1526,6 @@ static int __init vga_arb_device_init(void) PCI_ANY_ID, pdev)) != NULL) vga_arbiter_add_pci_device(pdev);
- vga_arb_select_default_device(); - - pr_info("loaded\n"); return rc; } subsys_initcall(vga_arb_device_init);
On Fri, Aug 20, 2021 at 06:08:23PM +0800, Huacai Chen wrote:
I'm open to merging this series but the v5.15 merge window will probably open on Sunday, and that's too close for a series of this size.
Moreover, the critical change is still buried in the middle of the last patch ("PCI/VGA: Rework default VGA device selection"). There's way too much going on in that single patch.
As I mentioned in [1], I think you can make a 1- or 2-line patch that will fix your problem, and I think *that's* the first thing we should do.
That would be a patch against drivers/gpu/vga/vgaarb.c, so it would be up to the DRM folks to decide whether to take it for v5.15, but at least it would be small enough to review it easily.
Bjorn
[1] https://lore.kernel.org/r/20210724001043.GA448782@bjorn-Precision-5520
Hi, Bjorn,
On Thu, Aug 26, 2021 at 4:17 AM Bjorn Helgaas helgaas@kernel.org wrote:
OK, let me try.
Huacai
Bjorn
[1] https://lore.kernel.org/r/20210724001043.GA448782@bjorn-Precision-5520
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