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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Linus Walleij <linus.walleij@linaro.org>,
        Sam Ravnborg <sam@ravnborg.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.4 011/109] drm: mcde: Fix display initialization problem
Date:   Tue, 14 Jul 2020 20:43:14 +0200
Message-Id: <20200714184106.066312422@linuxfoundation.org>
In-Reply-To: <20200714184105.507384017@linuxfoundation.org>
References: <20200714184105.507384017@linuxfoundation.org>
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From: Linus Walleij <linus.walleij@linaro.org>

[ Upstream commit b984b6d8b52372b98cce0a6ff6c2787f50665b87 ]

The following bug appeared in the MCDE driver/display
initialization during the recent merge window.

First the place we call drm_fbdev_generic_setup() in the
wrong place: this needs to be called AFTER calling
drm_dev_register() else we get this splat:

 ------------[ cut here ]------------
WARNING: CPU: 0 PID: 1 at ../drivers/gpu/drm/drm_fb_helper.c:2198 drm_fbdev_generic_setup+0x164/0x1a8
mcde a0350000.mcde: Device has not been registered.
Modules linked in:
Hardware name: ST-Ericsson Ux5x0 platform (Device Tree Support)
[<c010e704>] (unwind_backtrace) from [<c010a86c>] (show_stack+0x10/0x14)
[<c010a86c>] (show_stack) from [<c0414f38>] (dump_stack+0x9c/0xb0)
[<c0414f38>] (dump_stack) from [<c0121c8c>] (__warn+0xb8/0xd0)
[<c0121c8c>] (__warn) from [<c0121d18>] (warn_slowpath_fmt+0x74/0xb8)
[<c0121d18>] (warn_slowpath_fmt) from [<c04b154c>] (drm_fbdev_generic_setup+0x164/0x1a8)
[<c04b154c>] (drm_fbdev_generic_setup) from [<c04ed278>] (mcde_drm_bind+0xc4/0x160)
[<c04ed278>] (mcde_drm_bind) from [<c04f06b8>] (try_to_bring_up_master+0x15c/0x1a4)
(...)

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20200613223027.4189309-1-linus.walleij@linaro.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/mcde/mcde_drv.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/mcde/mcde_drv.c b/drivers/gpu/drm/mcde/mcde_drv.c
index 5649887d2b901..16e5fb9ec784d 100644
--- a/drivers/gpu/drm/mcde/mcde_drv.c
+++ b/drivers/gpu/drm/mcde/mcde_drv.c
@@ -215,7 +215,6 @@ static int mcde_modeset_init(struct drm_device *drm)
 
 	drm_mode_config_reset(drm);
 	drm_kms_helper_poll_init(drm);
-	drm_fbdev_generic_setup(drm, 32);
 
 	return 0;
 
@@ -282,6 +281,8 @@ static int mcde_drm_bind(struct device *dev)
 	if (ret < 0)
 		goto unbind;
 
+	drm_fbdev_generic_setup(drm, 32);
+
 	return 0;
 
 unbind:
-- 
2.25.1