Hi Rajat, On Fri, Jan 07, 2022 at 11:02:07AM -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 other 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> > Reviewed-by: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx> Acked-By: Benson Leung <bleung@xxxxxxxxxxxx> Hi Hans, Could you take this patch? This new driver in platform/chrome depends on the drm/drm_privacy_screen_driver.h header in your tree. Thanks! > --- > v5: * Add blank line, 2 more vowels to the driver name as per comments > * Add Dmitry's "Reviewed by" > v4: Same as v3 (No changes) > v3: * Renamed everything chromeos_priv_scrn_* to chromeos_privacy_screen_* > (and added line breaks to accommodate longer names within 80 chars) > * Cleanup / Added few comments > * Use the newly added drm_privacy_screen_get_drvdata() > * Provide the cleanup function chromeos_privacy_screen_remove() > v2: * Reword the commit log > * Make the Kconfig into a tristate > * Reorder the patches in the series. > > drivers/platform/chrome/Kconfig | 11 ++ > drivers/platform/chrome/Makefile | 1 + > .../platform/chrome/chromeos_privacy_screen.c | 153 ++++++++++++++++++ > 3 files changed, 165 insertions(+) > create mode 100644 drivers/platform/chrome/chromeos_privacy_screen.c > > diff --git a/drivers/platform/chrome/Kconfig b/drivers/platform/chrome/Kconfig > index ccc23d8686e8..75e93efd669f 100644 > --- a/drivers/platform/chrome/Kconfig > +++ b/drivers/platform/chrome/Kconfig > @@ -243,6 +243,17 @@ 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. When enabled, > + this should probably always be built into the kernel to avoid or > + minimize drm probe deferral. > + > source "drivers/platform/chrome/wilco_ec/Kconfig" > > endif # CHROMEOS_PLATFORMS > diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile > index f901d2e43166..5d4be9735d9d 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-$(CONFIG_CHROMEOS_PRIVACY_SCREEN) += chromeos_privacy_screen.o > obj-$(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_privacy_screen.c b/drivers/platform/chrome/chromeos_privacy_screen.c > new file mode 100644 > index 000000000000..77e9f5ee8e33 > --- /dev/null > +++ b/drivers/platform/chrome/chromeos_privacy_screen.c > @@ -0,0 +1,153 @@ > +// SPDX-License-Identifier: GPL-2.0 > + > +/* > + * ChromeOS Privacy Screen support > + * > + * Copyright (C) 2022 Google LLC > + * > + * This is the Chromeos privacy screen provider, present on certain chromebooks, > + * represented by a GOOG0010 device in the ACPI. This ACPI device, if present, > + * will cause the i915 drm driver to probe defer until this driver registers > + * the privacy-screen. > + */ > + > +#include <linux/acpi.h> > +#include <drm/drm_privacy_screen_driver.h> > + > +/* > + * The DSM (Device 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_privacy_screen_dsm_guid = > + GUID_INIT(0xc7033113, 0x8720, 0x4ceb, > + 0x90, 0x90, 0x9d, 0x52, 0xb3, 0xe5, 0x2d, 0x73); > + > +static void > +chromeos_privacy_screen_get_hw_state(struct drm_privacy_screen > + *drm_privacy_screen) > +{ > + union acpi_object *obj; > + acpi_handle handle; > + struct device *privacy_screen = > + drm_privacy_screen_get_drvdata(drm_privacy_screen); > + > + handle = acpi_device_handle(to_acpi_device(privacy_screen)); > + obj = acpi_evaluate_dsm(handle, &chromeos_privacy_screen_dsm_guid, > + PRIV_SCRN_DSM_REVID, > + PRIV_SCRN_DSM_FN_GET_STATUS, NULL); > + if (!obj) { > + dev_err(privacy_screen, > + "_DSM failed to get privacy-screen state\n"); > + return; > + } > + > + if (obj->type != ACPI_TYPE_INTEGER) > + dev_err(privacy_screen, > + "Bad _DSM to get privacy-screen state\n"); > + else if (obj->integer.value == 1) > + drm_privacy_screen->hw_state = drm_privacy_screen->sw_state = > + PRIVACY_SCREEN_ENABLED; > + else > + drm_privacy_screen->hw_state = drm_privacy_screen->sw_state = > + PRIVACY_SCREEN_DISABLED; > + > + ACPI_FREE(obj); > +} > + > +static int > +chromeos_privacy_screen_set_sw_state(struct drm_privacy_screen > + *drm_privacy_screen, > + enum drm_privacy_screen_status state) > +{ > + union acpi_object *obj = NULL; > + acpi_handle handle; > + struct device *privacy_screen = > + drm_privacy_screen_get_drvdata(drm_privacy_screen); > + > + handle = acpi_device_handle(to_acpi_device(privacy_screen)); > + > + if (state == PRIVACY_SCREEN_DISABLED) { > + obj = acpi_evaluate_dsm(handle, > + &chromeos_privacy_screen_dsm_guid, > + PRIV_SCRN_DSM_REVID, > + PRIV_SCRN_DSM_FN_DISABLE, NULL); > + } else if (state == PRIVACY_SCREEN_ENABLED) { > + obj = acpi_evaluate_dsm(handle, > + &chromeos_privacy_screen_dsm_guid, > + PRIV_SCRN_DSM_REVID, > + PRIV_SCRN_DSM_FN_ENABLE, NULL); > + } else { > + dev_err(privacy_screen, > + "Bad attempt to set privacy-screen status to %u\n", > + state); > + return -EINVAL; > + } > + > + if (!obj) { > + dev_err(privacy_screen, > + "_DSM failed to set privacy-screen state\n"); > + return -EIO; > + } > + > + drm_privacy_screen->hw_state = drm_privacy_screen->sw_state = state; > + ACPI_FREE(obj); > + return 0; > +} > + > +static const struct drm_privacy_screen_ops chromeos_privacy_screen_ops = { > + .get_hw_state = chromeos_privacy_screen_get_hw_state, > + .set_sw_state = chromeos_privacy_screen_set_sw_state, > +}; > + > +static int chromeos_privacy_screen_add(struct acpi_device *adev) > +{ > + struct drm_privacy_screen *drm_privacy_screen = > + drm_privacy_screen_register(&adev->dev, > + &chromeos_privacy_screen_ops, > + &adev->dev); > + > + if (IS_ERR(drm_privacy_screen)) { > + dev_err(&adev->dev, "Error registering privacy-screen\n"); > + return PTR_ERR(drm_privacy_screen); > + } > + > + adev->driver_data = drm_privacy_screen; > + dev_info(&adev->dev, "registered privacy-screen '%s'\n", > + dev_name(&drm_privacy_screen->dev)); > + > + return 0; > +} > + > +static int chromeos_privacy_screen_remove(struct acpi_device *adev) > +{ > + struct drm_privacy_screen *drm_privacy_screen = acpi_driver_data(adev); > + > + drm_privacy_screen_unregister(drm_privacy_screen); > + return 0; > +} > + > +static const struct acpi_device_id chromeos_privacy_screen_device_ids[] = { > + {"GOOG0010", 0}, /* Google's electronic privacy screen for eDP-1 */ > + {} > +}; > +MODULE_DEVICE_TABLE(acpi, chromeos_privacy_screen_device_ids); > + > +static struct acpi_driver chromeos_privacy_screen_driver = { > + .name = "chromeos_privacy_screen_driver", > + .class = "ChromeOS", > + .ids = chromeos_privacy_screen_device_ids, > + .ops = { > + .add = chromeos_privacy_screen_add, > + .remove = chromeos_privacy_screen_remove, > + }, > +}; > + > +module_acpi_driver(chromeos_privacy_screen_driver); > +MODULE_LICENSE("GPL v2"); > +MODULE_DESCRIPTION("ChromeOS ACPI Privacy Screen driver"); > +MODULE_AUTHOR("Rajat Jain <rajatja@xxxxxxxxxx>"); > -- > 2.34.1.575.g55b058a8bb-goog > -- Benson Leung Staff Software Engineer Chrome OS Kernel Google Inc. bleung@xxxxxxxxxx Chromium OS Project bleung@xxxxxxxxxxxx
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