From c10802b684c6bb00ecc6b4985805b05ebcc76a5d Mon Sep 17 00:00:00 2001 From: Peter Wu Date: Fri, 7 Sep 2018 00:18:10 +0200 Subject: [PATCH] drm/fb-helper: improve documentation and print warnings MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Clarify the relation between drm_fb_helper_fbdev_setup/teardown. Clarify requirements for the new generic fbdev emulation API and log some more details in case the driver does something wrong. Fix related typos. Cc: Noralf Trønnes Signed-off-by: Peter Wu Reviewed-by: Daniel Vetter Link: http://patchwork.freedesktop.org/patch/msgid/20180906221810.20170-5-peter@lekensteyn.nl Signed-off-by: Gerd Hoffmann --- drivers/gpu/drm/drm_fb_helper.c | 24 ++++++++++++++++++------ 1 file changed, 18 insertions(+), 6 deletions(-) diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c index 4b0dd20bccb8..73cf10adebbf 100644 --- a/drivers/gpu/drm/drm_fb_helper.c +++ b/drivers/gpu/drm/drm_fb_helper.c @@ -2821,7 +2821,9 @@ EXPORT_SYMBOL(drm_fb_helper_hotplug_event); * The caller must to provide a &drm_fb_helper_funcs->fb_probe callback * function. * - * See also: drm_fb_helper_initial_config() + * Use drm_fb_helper_fbdev_teardown() to destroy the fbdev. + * + * See also: drm_fb_helper_initial_config(), drm_fbdev_generic_setup(). * * Returns: * Zero on success or negative error code on failure. @@ -3037,7 +3039,7 @@ static struct fb_deferred_io drm_fbdev_defio = { * @fb_helper: fbdev helper structure * @sizes: describes fbdev size and scanout surface size * - * This function uses the client API to crate a framebuffer backed by a dumb buffer. + * This function uses the client API to create a framebuffer backed by a dumb buffer. * * The _sys_ versions are used for &fb_ops.fb_read, fb_write, fb_fillrect, * fb_copyarea, fb_imageblit. @@ -3165,8 +3167,10 @@ static int drm_fbdev_client_hotplug(struct drm_client_dev *client) if (dev->fb_helper) return drm_fb_helper_hotplug_event(dev->fb_helper); - if (!dev->mode_config.num_connector) + if (!dev->mode_config.num_connector) { + DRM_DEV_DEBUG(dev->dev, "No connectors found, will not create framebuffer!\n"); return 0; + } ret = drm_fb_helper_fbdev_setup(dev, fb_helper, &drm_fb_helper_generic_funcs, fb_helper->preferred_bpp, 0); @@ -3187,13 +3191,14 @@ static const struct drm_client_funcs drm_fbdev_client_funcs = { }; /** - * drm_fb_helper_generic_fbdev_setup() - Setup generic fbdev emulation + * drm_fbdev_generic_setup() - Setup generic fbdev emulation * @dev: DRM device * @preferred_bpp: Preferred bits per pixel for the device. * @dev->mode_config.preferred_depth is used if this is zero. * * This function sets up generic fbdev emulation for drivers that supports - * dumb buffers with a virtual address and that can be mmap'ed. + * dumb buffers with a virtual address and that can be mmap'ed. If the driver + * does not support these functions, it could use drm_fb_helper_fbdev_setup(). * * Restore, hotplug events and teardown are all taken care of. Drivers that do * suspend/resume need to call drm_fb_helper_set_suspend_unlocked() themselves. @@ -3206,6 +3211,8 @@ static const struct drm_client_funcs drm_fbdev_client_funcs = { * This function is safe to call even when there are no connectors present. * Setup will be retried on the next hotplug event. * + * The fbdev is destroyed by drm_dev_unregister(). + * * Returns: * Zero on success or negative error code on failure. */ @@ -3214,6 +3221,8 @@ int drm_fbdev_generic_setup(struct drm_device *dev, unsigned int preferred_bpp) struct drm_fb_helper *fb_helper; int ret; + WARN(dev->fb_helper, "fb_helper is already set!\n"); + if (!drm_fbdev_emulation) return 0; @@ -3224,12 +3233,15 @@ int drm_fbdev_generic_setup(struct drm_device *dev, unsigned int preferred_bpp) ret = drm_client_new(dev, &fb_helper->client, "fbdev", &drm_fbdev_client_funcs); if (ret) { kfree(fb_helper); + DRM_DEV_ERROR(dev->dev, "Failed to register client: %d\n", ret); return ret; } fb_helper->preferred_bpp = preferred_bpp; - drm_fbdev_client_hotplug(&fb_helper->client); + ret = drm_fbdev_client_hotplug(&fb_helper->client); + if (ret) + DRM_DEV_DEBUG(dev->dev, "client hotplug ret=%d\n", ret); return 0; } -- 2.30.2