linux-kernel - [PATCH v5 3/3] drm/privacy_screen_x86: Add entry for ChromeOS privacy-screen

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Message-Id: <20220107190208.95479-3-rajatja@google.com>
Date:   Fri,  7 Jan 2022 11:02:08 -0800
From:   Rajat Jain <rajatja@...gle.com>
To:     Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <mripard@...nel.org>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        Hans de Goede <hdegoede@...hat.com>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Benson Leung <bleung@...omium.org>,
        Henrique de Moraes Holschuh <hmh@....eng.br>,
        Mark Gross <markgross@...nel.org>,
        linux-kernel@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        ibm-acpi-devel@...ts.sourceforge.net,
        platform-driver-x86@...r.kernel.org, gwendal@...gle.com,
        seanpaul@...gle.com, marcheu@...gle.com, dtor@...gle.com,
        Dmitry Torokhov <dmitry.torokhov@...il.com>,
        Benson Leung <bleung@...gle.com>
Cc:     Rajat Jain <rajatja@...gle.com>, rajatxjain@...il.com
Subject: [PATCH v5 3/3] drm/privacy_screen_x86: Add entry for ChromeOS privacy-screen

Add a static entry in the x86 table, to detect and wait for
privacy-screen on some ChromeOS platforms.

Please note that this means that if CONFIG_CHROMEOS_PRIVACY_SCREEN is
enabled, and if "GOOG0010" device is found in ACPI, then the i915 probe
shall return EPROBE_DEFER until a platform driver actually registers the
privacy-screen: https://hansdegoede.livejournal.com/25948.html

Signed-off-by: Rajat Jain <rajatja@...gle.com>
Reviewed-by: Hans de Goede <hdegoede@...hat.com>
---
v5: * Add Hans' "Reviewed by"
v4: * Simplify the detect_chromeos_privacy_screen() function
    * Don't change the existing print statement
v3: * Remove the pr_info() from detect_chromeos_privacy_screen(), instead
      enhance the one already present in drm_privacy_screen_lookup_init()
v2: * Use #if instead of #elif
    * Reorder the patches in the series.
    * Rebased on drm-tip

 drivers/gpu/drm/drm_privacy_screen_x86.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/drivers/gpu/drm/drm_privacy_screen_x86.c b/drivers/gpu/drm/drm_privacy_screen_x86.c
index a2cafb294ca6..88802cd7a1ee 100644
--- a/drivers/gpu/drm/drm_privacy_screen_x86.c
+++ b/drivers/gpu/drm/drm_privacy_screen_x86.c
@@ -47,6 +47,13 @@ static bool __init detect_thinkpad_privacy_screen(void)
 }
 #endif
 
+#if IS_ENABLED(CONFIG_CHROMEOS_PRIVACY_SCREEN)
+static bool __init detect_chromeos_privacy_screen(void)
+{
+	return acpi_dev_present("GOOG0010", NULL, -1);
+}
+#endif
+
 static const struct arch_init_data arch_init_data[] __initconst = {
 #if IS_ENABLED(CONFIG_THINKPAD_ACPI)
 	{
@@ -58,6 +65,16 @@ static const struct arch_init_data arch_init_data[] __initconst = {
 		.detect = detect_thinkpad_privacy_screen,
 	},
 #endif
+#if IS_ENABLED(CONFIG_CHROMEOS_PRIVACY_SCREEN)
+	{
+		.lookup = {
+			.dev_id = NULL,
+			.con_id = NULL,
+			.provider = "privacy_screen-GOOG0010:00",
+		},
+		.detect = detect_chromeos_privacy_screen,
+	},
+#endif
 };
 
 void __init drm_privacy_screen_lookup_init(void)
-- 
2.34.1.575.g55b058a8bb-goog