[PATCH v4] platform/x86: Add new vga-switcheroo gmux driver for ACPI-driven muxes
Daniel Dadap
ddadap at nvidia.com
Thu Nov 12 18:53:15 UTC 2020
On 11/10/20 3:29 AM, Hans de Goede wrote:
> Hi Daniel,
Hi Hans,
> Quick self intro: I have take over drivers/platform/x86
> maintainership from Andy; and I'm working my way through
> the backlog of old patches in patchwork:
> https://patchwork.kernel.org/project/platform-driver-x86/list/
Thanks for the introduction. I believe we have corresponded in the past
regarding other issues. Thank you for following up on this patch set.
> On 9/2/20 7:38 PM, Daniel Dadap wrote:
>> Some upcoming notebook designs utilize display muxes driven by a
>> pair of ACPI methods, MXDM to query and configure the operational
>> mode of the mux (integrated only, discrete only, hybrid non-muxed,
>> hybrid with dynamic mux switching), and MXDS to query and set the
>> mux state when running in dynamic switch mode.
>>
>> Add a vga-switcheroo driver to support switching the mux on systems
>> with the ACPI MXDM/MXDS interface. The mux mode cannot be changed
>> dynamically (calling MXDM to change the mode won't have effect until
>> the next boot, and calling MXDM to read the mux mode returns the
>> active mode, not the mode that will be enabled on next boot), and
>> MXDS only works when the mux mode is set to dynamic switch, so this
>> driver will fail to load when MXDM reports any non-dynamic mode.
>>
>> This driver currently only supports systems with Intel integrated
>> graphics and NVIDIA discrete graphics. It will need to be updated if
>> designs are developed using the same interfaces which utilize GPUs
>> from other vendors.
>>
>> v2,v3: misc. fixes suggested by Barnabás Pőcze <pobrn at protonmail.com>
>> v4: misc. changes suggested by Lukas Wunner <lukas at wunner.de>
> According to the discussion archived here:
> https://patchwork.kernel.org/project/platform-driver-x86/patch/20200902173851.224368-1-ddadap@nvidia.com/
>
> Andy did a review and you promised a new version, but I don't see
> a newer version in patchwork. Can you please submit a new version
> addressing Andy's remarks ? Then I will review and merge the new
> version.
>
> In that discussion you also promised a new version of this patch:
> https://patchwork.kernel.org/project/platform-driver-x86/patch/20200731202154.11382-1-ddadap@nvidia.com/
>
> So please also submit a new version of that series.
You are right. I do have updated versions of those patches, but enough
time has passed that I do not recall if I tested them and failed to
follow up on the e-mail threads, or had yet to test them. So I will test
the updated patches and get them to you. Thanks.
> Thanks & Regards,
>
> Hans
>
>
>
>
>
>> Signed-off-by: Daniel Dadap <ddadap at nvidia.com>
>> ---
>> MAINTAINERS | 6 +
>> drivers/platform/x86/Kconfig | 9 ++
>> drivers/platform/x86/Makefile | 2 +
>> drivers/platform/x86/mxds-gmux.c | 265 +++++++++++++++++++++++++++++++
>> 4 files changed, 282 insertions(+)
>> create mode 100644 drivers/platform/x86/mxds-gmux.c
>>
>> diff --git a/MAINTAINERS b/MAINTAINERS
>> index eeff55560759..636c9259b345 100644
>> --- a/MAINTAINERS
>> +++ b/MAINTAINERS
>> @@ -11510,6 +11510,12 @@ L: linux-usb at vger.kernel.org
>> S: Maintained
>> F: drivers/usb/musb/
>>
>> +MXDS GMUX DRIVER
>> +M: Daniel Dadap <ddadap at nvidia.com>
>> +L: platform-driver-x86 at vger.kernel.org
>> +S: Supported
>> +F: drivers/platform/x86/mxds-gmux.c
>> +
>> MXL301RF MEDIA DRIVER
>> M: Akihiro Tsukada <tskd08 at gmail.com>
>> L: linux-media at vger.kernel.org
>> diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
>> index 0ad7ad8cf8e1..5d00ad1ffc0e 100644
>> --- a/drivers/platform/x86/Kconfig
>> +++ b/drivers/platform/x86/Kconfig
>> @@ -1368,6 +1368,15 @@ config INTEL_TELEMETRY
>> directly via debugfs files. Various tools may use
>> this interface for SoC state monitoring.
>>
>> +config MXDS_GMUX
>> + tristate "ACPI MXDS Gmux Driver"
>> + depends on ACPI_WMI
>> + depends on ACPI
>> + depends on VGA_SWITCHEROO
>> + help
>> + This driver provides support for ACPI-driven gmux devices which are
>> + present on some notebook designs with hybrid graphics.
>> +
>> endif # X86_PLATFORM_DEVICES
>>
>> config PMC_ATOM
>> diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
>> index 53408d965874..b79000733fae 100644
>> --- a/drivers/platform/x86/Makefile
>> +++ b/drivers/platform/x86/Makefile
>> @@ -146,3 +146,5 @@ obj-$(CONFIG_INTEL_TELEMETRY) += intel_telemetry_core.o \
>> intel_telemetry_pltdrv.o \
>> intel_telemetry_debugfs.o
>> obj-$(CONFIG_PMC_ATOM) += pmc_atom.o
>> +
>> +obj-$(CONFIG_MXDS_GMUX) += mxds-gmux.o
>> diff --git a/drivers/platform/x86/mxds-gmux.c b/drivers/platform/x86/mxds-gmux.c
>> new file mode 100644
>> index 000000000000..dd7f6edaf0f3
>> --- /dev/null
>> +++ b/drivers/platform/x86/mxds-gmux.c
>> @@ -0,0 +1,265 @@
>> +// SPDX-License-Identifier: GPL-2.0-only
>> +/*
>> + * mxds-gmux: vga_switcheroo mux handler for ACPI MXDS muxes
>> + *
>> + * Copyright (C) 2020 NVIDIA Corporation
>> + *
>> + * This program is free software; you can redistribute it and/or modify it
>> + * under the terms and conditions of the GNU General Public License,
>> + * version 2, as published by the Free Software Foundation.
>> + *
>> + * This program is distributed in the hope that it will be useful, but WITHOUT
>> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
>> + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
>> + * more details.
>> + *
>> + * You should have received a copy of the GNU General Public License
>> + * along with this program; if not, see <http://www.gnu.org/licenses>.
>> + *
>> + */
>> +
>> +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
>> +
>> +#include <linux/module.h>
>> +#include <linux/acpi.h>
>> +#include <linux/pci.h>
>> +#include <linux/vga_switcheroo.h>
>> +#include <linux/delay.h>
>> +
>> +MODULE_LICENSE("GPL v2");
>> +MODULE_DESCRIPTION("vga_switcheroo mux handler for ACPI MXDS muxes");
>> +MODULE_AUTHOR("Daniel Dadap <ddadap at nvidia.com>");
>> +
>> +/*
>> + * The mux doesn't have its own ACPI HID/CID, or WMI wrapper, so key off of
>> + * the WMI wrapper for the related WMAA method for backlight control.
>> + */
>> +MODULE_ALIAS("wmi:603E9613-EF25-4338-A3D0-C46177516DB7");
>> +
>> +static struct pci_dev *ig_dev, *dg_dev;
>> +static acpi_handle internal_mux_handle;
>> +static acpi_handle external_mux_handle;
>> +
>> +enum acpi_method {
>> + MXDM = 0,
>> + MXDS,
>> + NUM_ACPI_METHODS
>> +};
>> +
>> +static char *acpi_methods[NUM_ACPI_METHODS] = {
>> + [MXDM] = "MXDM",
>> + [MXDS] = "MXDS",
>> +};
>> +
>> +enum mux_mode_command {
>> + MUX_MODE_GET = 0,
>> +};
>> +
>> +enum mux_mode {
>> + MUX_MODE_DGPU_ONLY = 1,
>> + MUX_MODE_IGPU_ONLY = 2,
>> + MUX_MODE_MSHYBRID = 3, /* Dual GPU, mux switched to iGPU */
>> + MUX_MODE_DYNAMIC = 4, /* Dual GPU, dynamic mux switching */
>> +};
>> +
>> +/*
>> + * Call MXDS with argument value 0 to read the current state.
>> + * When reading, a return value of 1 means iGPU and 2 means dGPU.
>> + * Call MXDS with bit 0 set to change the current state.
>> + * When changing state, clear bit 4 for iGPU and set bit 4 for dGPU.
>> + */
>> +
>> +enum mux_state {
>> + MUX_STATE_IGPU = 1,
>> + MUX_STATE_DGPU = 2,
>> +};
>> +
>> +enum mux_state_command {
>> + MUX_STATE_GET = 0,
>> + MUX_STATE_SET_IGPU = BIT(0),
>> + MUX_STATE_SET_DGPU = BIT(4) | BIT(0),
>> +};
>> +
>> +static acpi_integer acpi_helper(acpi_handle handle, enum acpi_method method,
>> + acpi_integer action)
>> +{
>> + union acpi_object arg = {
>> + .integer = { .type = ACPI_TYPE_INTEGER, .value = action }
>> + };
>> + struct acpi_object_list in = {.count = 1, .pointer = &arg};
>> + acpi_integer ret;
>> + acpi_status status;
>> +
>> + status = acpi_evaluate_integer(handle, acpi_methods[method], &in, &ret);
>> +
>> + if (ACPI_FAILURE(status)) {
>> + pr_err("ACPI %s failed: %s\n", acpi_methods[method],
>> + acpi_format_exception(status));
>> + return 0;
>> + }
>> +
>> + return ret;
>> +}
>> +
>> +static acpi_integer get_mux_mode(acpi_handle handle)
>> +{
>> + return acpi_helper(handle, MXDM, MUX_MODE_GET);
>> +}
>> +
>> +static acpi_integer get_mux_state(acpi_handle handle)
>> +{
>> + return acpi_helper(handle, MXDS, MUX_STATE_GET);
>> +}
>> +
>> +static void set_mux_state(acpi_handle handle, enum mux_state state)
>> +{
>> + enum mux_state_command command;
>> +
>> + switch (state) {
>> + case MUX_STATE_IGPU:
>> + command = MUX_STATE_SET_IGPU;
>> + break;
>> + case MUX_STATE_DGPU:
>> + command = MUX_STATE_SET_DGPU;
>> + break;
>> + default:
>> + return;
>> + }
>> +
>> + acpi_helper(handle, MXDS, command);
>> +}
>> +
>> +static int mxds_gmux_switchto(enum vga_switcheroo_client_id id)
>> +{
>> + enum mux_state state;
>> +
>> + switch (id) {
>> + case VGA_SWITCHEROO_IGD:
>> + state = MUX_STATE_IGPU;
>> + break;
>> + case VGA_SWITCHEROO_DIS:
>> + state = MUX_STATE_DGPU;
>> + break;
>> + default:
>> + return -EINVAL;
>> + }
>> +
>> + if (internal_mux_handle) {
>> + set_mux_state(internal_mux_handle, state);
>> + if (get_mux_state(internal_mux_handle) != state)
>> + return -EAGAIN;
>> + }
>> +
>> + if (external_mux_handle) {
>> + set_mux_state(external_mux_handle, state);
>> + if (get_mux_state(external_mux_handle) != state)
>> + return -EAGAIN;
>> + }
>> +
>> + /* DP AUX can take up to 100ms to settle after mux switch */
>> + mdelay(100);
>> +
>> + return 0;
>> +}
>> +
>> +static enum vga_switcheroo_client_id mxds_gmux_get_client_id(
>> + struct pci_dev *dev)
>> +{
>> + if (dev == ig_dev)
>> + return VGA_SWITCHEROO_IGD;
>> + if (dev == dg_dev)
>> + return VGA_SWITCHEROO_DIS;
>> +
>> + return VGA_SWITCHEROO_UNKNOWN_ID;
>> +}
>> +
>> +static const struct vga_switcheroo_handler handler = {
>> + .switchto = mxds_gmux_switchto,
>> + .get_client_id = mxds_gmux_get_client_id,
>> +};
>> +
>> +static acpi_status find_acpi_methods(
>> + acpi_handle object, u32 nesting_level, void *context,
>> + void **return_value)
>> +{
>> + acpi_handle search;
>> +
>> + /* If either MXDM or MXDS is missing, we can't use this object */
>> + if (acpi_get_handle(object, "MXDM", &search))
>> + return AE_OK;
>> + if (acpi_get_handle(object, "MXDS", &search))
>> + return AE_OK;
>> +
>> + /* MXDS only works when MXDM indicates dynamic mode */
>> + if (get_mux_mode(object) != MUX_MODE_DYNAMIC)
>> + return AE_OK;
>> +
>> + /* Internal display has _BCL; external does not */
>> + if (acpi_get_handle(object, "_BCL", &search))
>> + external_mux_handle = object;
>> + else
>> + internal_mux_handle = object;
>> +
>> + return AE_OK;
>> +}
>> +
>> +static int __init mxds_gmux_init(void)
>> +{
>> + int ret = 0;
>> + struct pci_dev *dev = NULL;
>> +
>> + /* Currently only supports Intel integrated and NVIDIA discrete GPUs */
>> + while ((dev = pci_get_class(PCI_CLASS_DISPLAY_VGA << 8, dev))) {
>> + /* Ignore eGPU */
>> + if (pci_is_thunderbolt_attached(dev))
>> + continue;
>> +
>> + switch (dev->vendor) {
>> + case PCI_VENDOR_ID_INTEL:
>> + pci_dev_put(ig_dev);
>> + ig_dev = pci_dev_get(dev);
>> + break;
>> + case PCI_VENDOR_ID_NVIDIA:
>> + pci_dev_put(dg_dev);
>> + dg_dev = pci_dev_get(dev);
>> + break;
>> + default:
>> + break;
>> + }
>> + }
>> +
>> + /* Require both integrated and discrete GPUs */
>> + if (!ig_dev || !dg_dev) {
>> + ret = -ENODEV;
>> + goto done;
>> + }
>> +
>> + acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT, ACPI_UINT32_MAX,
>> + find_acpi_methods, NULL, NULL, NULL);
>> +
>> + /* Require at least one mux */
>> + if (!internal_mux_handle && !external_mux_handle) {
>> + ret = -ENODEV;
>> + goto done;
>> + }
>> +
>> + ret = vga_switcheroo_register_handler(&handler, 0);
>> +
>> +done:
>> +
>> + if (ret) {
>> + pci_dev_put(ig_dev);
>> + pci_dev_put(dg_dev);
>> + }
>> +
>> + return ret;
>> +}
>> +module_init(mxds_gmux_init);
>> +
>> +static void __exit mxds_gmux_exit(void)
>> +{
>> + vga_switcheroo_unregister_handler();
>> + pci_dev_put(ig_dev);
>> + pci_dev_put(dg_dev);
>> +}
>> +module_exit(mxds_gmux_exit);
>>
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