diff options
| author | Hans de Goede | 2022-02-09 17:13:42 +0100 |
|---|---|---|
| committer | Rafael J. Wysocki | 2022-02-09 19:42:58 +0100 |
| commit | 3eb616b26408ac813c67280cf883f36d98b8441d (patch) | |
| tree | 400369d681f31251007b48d43e4682c68d08769f /arch | |
| parent | 7f7b4236f2040d19df1ddaf30047128b41e78de7 (diff) | |
x86/PCI: revert "Ignore E820 reservations for bridge windows on newer systems"
Commit 7f7b4236f204 ("x86/PCI: Ignore E820 reservations for bridge windows
on newer systems") fixes the touchpad not working on laptops like
the Lenovo IdeaPad 3 15IIL05 and the Lenovo IdeaPad 5 14IIL05, as well as
fixing thunderbolt hotplug issues on the Lenovo Yoga C940.
Unfortunately it turns out that this is causing issues with suspend/resume
on Lenovo ThinkPad X1 Carbon Gen 2 laptops. So, per the no regressions
policy, rever this. Note I'm looking into another fix for the issues this
fixed.
Fixes: 7f7b4236f204 ("x86/PCI: Ignore E820 reservations for bridge windows on newer systems")
BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=2029207
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kernel/resource.c | 23 |
1 files changed, 1 insertions, 22 deletions
diff --git a/arch/x86/kernel/resource.c b/arch/x86/kernel/resource.c index 9ae64f9af956..9b9fb7882c20 100644 --- a/arch/x86/kernel/resource.c +++ b/arch/x86/kernel/resource.c @@ -1,5 +1,4 @@ // SPDX-License-Identifier: GPL-2.0 -#include <linux/dmi.h> #include <linux/ioport.h> #include <asm/e820/api.h> @@ -24,31 +23,11 @@ static void resource_clip(struct resource *res, resource_size_t start, res->start = end + 1; } -/* - * Some BIOS-es contain a bug where they add addresses which map to - * system RAM in the PCI host bridge window returned by the ACPI _CRS - * method, see commit 4dc2287c1805 ("x86: avoid E820 regions when - * allocating address space"). To avoid this Linux by default excludes - * E820 reservations when allocating addresses since 2010. - * In 2019 some systems have shown-up with E820 reservations which cover - * the entire _CRS returned PCI host bridge window, causing all attempts - * to assign memory to PCI BARs to fail if Linux uses E820 reservations. - * - * Ideally Linux would fully stop using E820 reservations, but then - * the old systems this was added for will regress. - * Instead keep the old behavior for old systems, while ignoring the - * E820 reservations for any systems from now on. - */ static void remove_e820_regions(struct resource *avail) { - int i, year = dmi_get_bios_year(); + int i; struct e820_entry *entry; - if (year >= 2018) - return; - - pr_info_once("PCI: Removing E820 reservations from host bridge windows\n"); - for (i = 0; i < e820_table->nr_entries; i++) { entry = &e820_table->entries[i]; |