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

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Date:   Wed, 15 May 2019 00:20:59 +0200
From:   Linus Walleij <linus.walleij@...aro.org>
To:     Guenter Roeck <linux@...ck-us.net>
Cc:     Eric Anholt <eric@...olt.net>, David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        "open list:DRM PANEL DRIVERS" <dri-devel@...ts.freedesktop.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] drm/pl111: Initialize clock spinlock early

On Mon, May 13, 2019 at 4:46 PM Guenter Roeck <linux@...ck-us.net> wrote:

> 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>

Applied to drm-misc-next-fixes and pushed.

Out of curiosity: do you have a "real" Integrator/CP or is this
QEMU?

Yours,
Linus Walleij