linux-kernel - [PATCH] drm/pl111: Initialize clock spinlock early

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Message-Id: <1557758781-23586-1-git-send-email-linux@roeck-us.net>
Date:   Mon, 13 May 2019 07:46:21 -0700
From:   Guenter Roeck <linux@...ck-us.net>
To:     Eric Anholt <eric@...olt.net>
Cc:     David Airlie <airlied@...ux.ie>, Daniel Vetter <daniel@...ll.ch>,
        dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
        Guenter Roeck <linux@...ck-us.net>,
        Linus Walleij <linus.walleij@...aro.org>
Subject: [PATCH] drm/pl111: Initialize clock spinlock early

The following warning is seen on systems with broken clock divider.

INFO: trying to register non-static key.
the code is fine but needs lockdep annotation.
turning off the locking correctness validator.
CPU: 0 PID: 1 Comm: swapper Not tainted 5.1.0-09698-g1fb3b52 #1
Hardware name: ARM Integrator/CP (Device Tree)
[<c0011be8>] (unwind_backtrace) from [<c000ebb8>] (show_stack+0x10/0x18)
[<c000ebb8>] (show_stack) from [<c07d3fd0>] (dump_stack+0x18/0x24)
[<c07d3fd0>] (dump_stack) from [<c0060d48>] (register_lock_class+0x674/0x6f8)
[<c0060d48>] (register_lock_class) from [<c005de2c>]
	(__lock_acquire+0x68/0x2128)
[<c005de2c>] (__lock_acquire) from [<c0060408>] (lock_acquire+0x110/0x21c)
[<c0060408>] (lock_acquire) from [<c07f755c>] (_raw_spin_lock+0x34/0x48)
[<c07f755c>] (_raw_spin_lock) from [<c0536c8c>]
	(pl111_display_enable+0xf8/0x5fc)
[<c0536c8c>] (pl111_display_enable) from [<c0502f54>]
	(drm_atomic_helper_commit_modeset_enables+0x1ec/0x244)

Since commit eedd6033b4c8 ("drm/pl111: Support variants with broken clock
divider"), the spinlock is not initialized if the clock divider is broken.
Initialize it earlier to fix the problem.

Fixes: eedd6033b4c8 ("drm/pl111: Support variants with broken clock divider")
Cc: Linus Walleij <linus.walleij@...aro.org>
Signed-off-by: Guenter Roeck <linux@...ck-us.net>
---
 drivers/gpu/drm/pl111/pl111_display.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/pl111/pl111_display.c b/drivers/gpu/drm/pl111/pl111_display.c
index 0c5d391f0a8f..4501597f30ab 100644
--- a/drivers/gpu/drm/pl111/pl111_display.c
+++ b/drivers/gpu/drm/pl111/pl111_display.c
@@ -531,14 +531,15 @@ pl111_init_clock_divider(struct drm_device *drm)
 		dev_err(drm->dev, "CLCD: unable to get clcdclk.\n");
 		return PTR_ERR(parent);
 	}
+
+	spin_lock_init(&priv->tim2_lock);
+
 	/* If the clock divider is broken, use the parent directly */
 	if (priv->variant->broken_clockdivider) {
 		priv->clk = parent;
 		return 0;
 	}
 	parent_name = __clk_get_name(parent);
-
-	spin_lock_init(&priv->tim2_lock);
 	div->init = &init;
 
 	ret = devm_clk_hw_register(drm->dev, div);
-- 
2.7.4