linux-kernel - [PATCH 4/5] drm: Add a drm_drv

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Message-Id: <20211103105436.1024242-1-javierm@redhat.com>
Date:   Wed,  3 Nov 2021 11:54:36 +0100
From:   Javier Martinez Canillas <javierm@...hat.com>
To:     linux-kernel@...r.kernel.org
Cc:     Pekka Paalanen <pekka.paalanen@...labora.com>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        Peter Robinson <pbrobinson@...il.com>,
        Daniel Vetter <daniel.vetter@...ll.ch>,
        Neal Gompa <ngompa13@...il.com>,
        Michel Dänzer <michel@...nzer.net>,
        Javier Martinez Canillas <javierm@...hat.com>
Subject: [PATCH 4/5] drm: Add a drm_drv_enabled() helper function

DRM drivers can use this to determine whether they can be enabled or not.

For now it's just a wrapper around drm_modeset_disabled() but having the
indirection level will allow to add other conditions besides "nomodeset".

Suggested-by: Thomas Zimmermann <tzimmermann@...e.de>
Signed-off-by: Javier Martinez Canillas <javierm@...hat.com>
---

 drivers/gpu/drm/drm_drv.c | 21 +++++++++++++++++++++
 include/drm/drm_drv.h     |  1 +
 2 files changed, 22 insertions(+)

diff --git drivers/gpu/drm/drm_drv.c drivers/gpu/drm/drm_drv.c
index 8214a0b1ab7f..70ef08941e06 100644
--- drivers/gpu/drm/drm_drv.c
+++ drivers/gpu/drm/drm_drv.c
@@ -975,6 +975,27 @@ int drm_dev_set_unique(struct drm_device *dev, const char *name)
 }
 EXPORT_SYMBOL(drm_dev_set_unique);
 
+/**
+ * drm_drv_enabled - Checks if a DRM driver can be enabled
+ * @driver: DRM driver to check
+ *
+ * Checks whether a DRM driver can be enabled or not. This may be the case
+ * if the "nomodeset" kernel command line parameter is used.
+ *
+ * Returns:
+ * True if the DRM driver is enabled and false otherwise.
+ */
+bool drm_drv_enabled(const struct drm_driver *driver)
+{
+	if (drm_modeset_disabled()) {
+		DRM_INFO("%s driver is disabled\n", driver->name);
+		return false;
+	}
+
+	return true;
+}
+EXPORT_SYMBOL(drm_drv_enabled);
+
 /*
  * DRM Core
  * The DRM core module initializes all global DRM objects and makes them
diff --git include/drm/drm_drv.h include/drm/drm_drv.h
index 0cd95953cdf5..48f2b6eec012 100644
--- include/drm/drm_drv.h
+++ include/drm/drm_drv.h
@@ -598,5 +598,6 @@ static inline bool drm_drv_uses_atomic_modeset(struct drm_device *dev)
 
 int drm_dev_set_unique(struct drm_device *dev, const char *name);
 
+bool drm_drv_enabled(const struct drm_driver *driver);
 
 #endif
-- 
2.33.1