Hi Rajat, On Fri, Dec 17, 2021 at 12:28:49PM -0800, Rajat Jain wrote: > This adds the ACPI driver for the ChromeOS privacy screen that is > present on some chromeos devices. > > Note that ideally, we'd want this privacy screen driver to be probed > BEFORE the drm probe in order to avoid a drm probe deferral: > https://hansdegoede.livejournal.com/25948.html > > In practise, I found that ACPI drivers are bound to their devices AFTER > the drm probe on chromebooks. So on chromebooks with privacy-screen, > this patch along with the next one in this series results in a probe > deferral of about 250ms for i915 driver. However, it did not result in > any user noticeable delay of splash screen in my personal experience. > > In future if this probe deferral turns out to be an issue, we can > consider turning this ACPI driver into something that is probed > earlier than the drm drivers. > > Signed-off-by: Rajat Jain <rajatja@xxxxxxxxxx> > --- > v2: * Reword the commit log > * Make the Kconfig into a tristate > * Reorder the patches in the series. > > drivers/platform/chrome/Kconfig | 9 ++ > drivers/platform/chrome/Makefile | 1 + > drivers/platform/chrome/chromeos_priv_scrn.c | 132 +++++++++++++++++++ > 3 files changed, 142 insertions(+) > create mode 100644 drivers/platform/chrome/chromeos_priv_scrn.c > > diff --git a/drivers/platform/chrome/Kconfig b/drivers/platform/chrome/Kconfig > index ccc23d8686e8..d1c209a45a62 100644 > --- a/drivers/platform/chrome/Kconfig > +++ b/drivers/platform/chrome/Kconfig > @@ -243,6 +243,15 @@ config CROS_USBPD_NOTIFY > To compile this driver as a module, choose M here: the > module will be called cros_usbpd_notify. > > +config CHROMEOS_PRIVACY_SCREEN > + tristate "ChromeOS Privacy Screen support" > + depends on ACPI > + depends on DRM > + select DRM_PRIVACY_SCREEN > + help > + This driver provides the support needed for the in-built electronic > + privacy screen that is present on some ChromeOS devices. > + > source "drivers/platform/chrome/wilco_ec/Kconfig" > > endif # CHROMEOS_PLATFORMS > diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile > index f901d2e43166..cfa0bb4e9e34 100644 > --- a/drivers/platform/chrome/Makefile > +++ b/drivers/platform/chrome/Makefile > @@ -4,6 +4,7 @@ > CFLAGS_cros_ec_trace.o:= -I$(src) > > obj-$(CONFIG_CHROMEOS_LAPTOP) += chromeos_laptop.o > +obj-$(CONFIG_CHROMEOS_PRIVACY_SCREEN) += chromeos_priv_scrn.o > obj-$(CONFIG_CHROMEOS_PSTORE) += chromeos_pstore.o > obj-$(CONFIG_CHROMEOS_TBMC) += chromeos_tbmc.o > obj-$(CONFIG_CROS_EC) += cros_ec.o > diff --git a/drivers/platform/chrome/chromeos_priv_scrn.c b/drivers/platform/chrome/chromeos_priv_scrn.c > new file mode 100644 > index 000000000000..a4cbf5c79c2a > --- /dev/null > +++ b/drivers/platform/chrome/chromeos_priv_scrn.c I think we can spare a few more characters :) chromeos_privacy_screen.c maybe? And also see if maybe variables in the code are not that unseemly long even if not abbreviated? > @@ -0,0 +1,132 @@ > +// SPDX-License-Identifier: GPL-2.0 > + > +/* > + * chromeos_priv_scrn.c - ChromeOS Privacy Screen support I'd avoid mentioning file name as those tend to change. > + * > + * Copyright (C) 2022 The Chromium OS Authors This is not correct copyright for kernel contributions. It should be attributed to "Google LLC". Note that it is different from CrOS userspace. > + * > + */ > + > +#include <linux/acpi.h> > +#include <drm/drm_privacy_screen_driver.h> > + > +/* > + * The DSM (Define Specific Method) constants below are the agreed API with > + * the firmware team, on how to control privacy screen using ACPI methods. > + */ > +#define PRIV_SCRN_DSM_REVID 1 /* DSM version */ > +#define PRIV_SCRN_DSM_FN_GET_STATUS 1 /* Get privacy screen status */ > +#define PRIV_SCRN_DSM_FN_ENABLE 2 /* Enable privacy screen */ > +#define PRIV_SCRN_DSM_FN_DISABLE 3 /* Disable privacy screen */ > + > +static const guid_t chromeos_priv_scrn_dsm_guid = > + GUID_INIT(0xc7033113, 0x8720, 0x4ceb, > + 0x90, 0x90, 0x9d, 0x52, 0xb3, 0xe5, 0x2d, 0x73); > + > +static void > +chromeos_priv_scrn_get_hw_state(struct drm_privacy_screen *drm_priv_scrn) > +{ > + union acpi_object *obj; > + acpi_handle handle; > + struct device *priv_scrn = drm_priv_scrn->dev.parent; This is really bad that we need to poke into internals of drm_privacy_screen to get to "our" device. I think there is only one consume of the privacy screen API at the moment, the thinkpad driver, so maybe it is not too late to change drm_privacy_screen_register() to either accept instance of struct drm_privacy_screen (which then could be embedded into something) or accept a void pointer to attach arbitrary data to it, and then add drm_privacy_screen_get_drvdata() to get to that pointer. > + > + if (!priv_scrn) > + return; This should not happen regardless. > + > + handle = acpi_device_handle(to_acpi_device(priv_scrn)); > + obj = acpi_evaluate_dsm(handle, &chromeos_priv_scrn_dsm_guid, > + PRIV_SCRN_DSM_REVID, > + PRIV_SCRN_DSM_FN_GET_STATUS, NULL); > + if (!obj) { > + dev_err(priv_scrn, "_DSM failed to get privacy-screen state\n"); Can we do something about it? A dedicated status? Also, can we print ACPI-specific error? > + return; > + } > + > + if (obj->type != ACPI_TYPE_INTEGER) > + dev_err(priv_scrn, "Bad _DSM to get privacy-screen state\n"); Same here. > + else if (obj->integer.value == 1) > + drm_priv_scrn->hw_state = drm_priv_scrn->sw_state = > + PRIVACY_SCREEN_ENABLED; > + else > + drm_priv_scrn->hw_state = drm_priv_scrn->sw_state = > + PRIVACY_SCREEN_DISABLED; > + > + ACPI_FREE(obj); > +} > + > +static int > +chromeos_priv_scrn_set_sw_state(struct drm_privacy_screen *drm_priv_scrn, > + enum drm_privacy_screen_status state) > +{ > + union acpi_object *obj = NULL; > + acpi_handle handle; > + struct device *priv_scrn = drm_priv_scrn->dev.parent; > + > + if (!priv_scrn) > + return -ENODEV; This should not happen regardless. > + > + handle = acpi_device_handle(to_acpi_device(priv_scrn)); > + > + if (state == PRIVACY_SCREEN_DISABLED) { > + obj = acpi_evaluate_dsm(handle, &chromeos_priv_scrn_dsm_guid, > + PRIV_SCRN_DSM_REVID, > + PRIV_SCRN_DSM_FN_DISABLE, NULL); > + } else if (state == PRIVACY_SCREEN_ENABLED) { > + obj = acpi_evaluate_dsm(handle, &chromeos_priv_scrn_dsm_guid, > + PRIV_SCRN_DSM_REVID, > + PRIV_SCRN_DSM_FN_ENABLE, NULL); > + } else { > + dev_err(priv_scrn, "Bad attempt to set privacy-screen status\n"); > + return -EINVAL; Print state to aid in tracking bugs? > + } > + > + if (!obj) { > + dev_err(priv_scrn, "_DSM failed to set privacy-screen state\n"); Can we print ACPI-specific error? > + return -EIO; > + } > + > + drm_priv_scrn->hw_state = drm_priv_scrn->sw_state = state; > + ACPI_FREE(obj); > + return 0; > +} > + > +static const struct drm_privacy_screen_ops chromeos_priv_scrn_ops = { > + .get_hw_state = chromeos_priv_scrn_get_hw_state, > + .set_sw_state = chromeos_priv_scrn_set_sw_state, > +}; > + > +static int chromeos_priv_scrn_add(struct acpi_device *adev) > +{ > + struct drm_privacy_screen *drm_priv_scrn = > + drm_privacy_screen_register(&adev->dev, &chromeos_priv_scrn_ops); > + > + if (IS_ERR(drm_priv_scrn)) { > + dev_err(&adev->dev, "Error registering privacy-screen\n"); > + return PTR_ERR(drm_priv_scrn); > + } > + > + dev_info(&adev->dev, "registered privacy-screen '%s'\n", > + dev_name(&drm_priv_scrn->dev)); I don't think we need be this noisy. > + > + return 0; > +} > + > +static const struct acpi_device_id chromeos_priv_scrn_device_ids[] = { > + {"GOOG0010", 0}, /* Google's electronic privacy screen for eDP-1 */ > + {} > +}; > +MODULE_DEVICE_TABLE(acpi, chromeos_priv_scrn_device_ids); > + > +static struct acpi_driver chromeos_priv_scrn_driver = { > + .name = "chromeos_priv_scrn_drvr", > + .class = "ChromeOS", > + .ids = chromeos_priv_scrn_device_ids, > + .ops = { > + .add = chromeos_priv_scrn_add, We don't need any cleanup? > + }, > +}; > + > +module_acpi_driver(chromeos_priv_scrn_driver); > +MODULE_LICENSE("GPL v2"); > +MODULE_DESCRIPTION("ChromeOS ACPI Privacy Screen driver"); > +MODULE_AUTHOR("Rajat Jain <rajatja@xxxxxxxxxx>"); > -- > 2.34.1.307.g9b7440fafd-goog > Thanks. -- Dmitry
