Re: [PATCH v2 2/2] drm/privacy_screen_x86: Add entry for ChromeOS privacy-screen

On Fri, Dec 17, 2021 at 12:28:50PM -0800, Rajat Jain wrote:

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@google.com

v2: * Use #if instead of #elif * Reorder the patches in the series. * Rebased on drm-tip

drivers/gpu/drm/drm_privacy_screen_x86.c | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+)

diff --git a/drivers/gpu/drm/drm_privacy_screen_x86.c b/drivers/gpu/drm/drm_privacy_screen_x86.c index a2cafb294ca6..0c5699ad70a3 100644 --- a/drivers/gpu/drm/drm_privacy_screen_x86.c +++ b/drivers/gpu/drm/drm_privacy_screen_x86.c @@ -47,6 +47,18 @@ static bool __init detect_thinkpad_privacy_screen(void) } #endif

+#if IS_ENABLED(CONFIG_CHROMEOS_PRIVACY_SCREEN) +static bool __init detect_chromeos_privacy_screen(void)

Does marking this __init work in case there is a deferral? Can it happen that privacy screen is a module and so will get loaded only after we discarded __init sections.

+{

• if (!acpi_dev_present("GOOG0010", NULL, -1))

• return false;
  

• pr_info("%s: Need to wait for ChromeOS privacy-screen drvr", __func__);

I still do not see how this message is helpful. If it is really desired, I'd put something into the code that calls into lookups.

• return true;

+} +#endif

static const struct arch_init_data arch_init_data[] __initconst = { #if IS_ENABLED(CONFIG_THINKPAD_ACPI) { @@ -58,6 +70,16 @@ 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)

2.34.1.307.g9b7440fafd-goog

Thanks.