[Intel-gfx] [PATCH 1/1] drm/i915: Get the correct wakeref for reading HOTPLUG_EN et al.

[Chris Wilson]

Quoting Arkadiusz Hiler (2019-09-12 13:54:18)
> Without it we get:
>  Unclaimed read from register 0x1e1110
>  WARNING: CPU: 2 PID: 1029 at drivers/gpu/drm/i915/intel_uncore.c:1101 __unclaimed_reg_debug+0x40/0x50 [i915]
>  Call Trace:
>   fwtable_read32+0x233/0x300 [i915]
>   i915_interrupt_info+0xa73/0xd60 [i915]
>   seq_read+0xdb/0x3c0
>   full_proxy_read+0x51/0x80
>   vfs_read+0x9e/0x160
>   ksys_read+0x8f/0xe0
>   do_syscall_64+0x55/0x1c0
>   entry_SYSCALL_64_after_hwframe+0x49/0xbe
> 
> Cc: Chris Wilson <chris at chris-wilson.co.uk>
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=109824
> Signed-off-by: Arkadiusz Hiler <arkadiusz.hiler at intel.com>
> ---
>  drivers/gpu/drm/i915/i915_debugfs.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
> index e5835337f022..29f3436167a2 100644
> --- a/drivers/gpu/drm/i915/i915_debugfs.c
> +++ b/drivers/gpu/drm/i915/i915_debugfs.c
> @@ -534,6 +534,7 @@ static int i915_interrupt_info(struct seq_file *m, void *data)
>  
>                 gen8_display_interrupt_info(m);
>         } else if (IS_VALLEYVIEW(dev_priv)) {
> +               intel_wakeref_t pref;

checkpath will complain about missing newline between variable block and
code.

>                 seq_printf(m, "Display IER:\t%08x\n",
>                            I915_READ(VLV_IER));
>                 seq_printf(m, "Display IIR:\t%08x\n",
> @@ -544,7 +545,6 @@ static int i915_interrupt_info(struct seq_file *m, void *data)
>                            I915_READ(VLV_IMR));
>                 for_each_pipe(dev_priv, pipe) {
>                         enum intel_display_power_domain power_domain;
> -                       intel_wakeref_t pref;
>  
>                         power_domain = POWER_DOMAIN_PIPE(pipe);
>                         pref = intel_display_power_get_if_enabled(dev_priv,
> @@ -578,12 +578,14 @@ static int i915_interrupt_info(struct seq_file *m, void *data)
>                 seq_printf(m, "PM IMR:\t\t%08x\n",
>                            I915_READ(GEN6_PMIMR));
>  
> +               pref = intel_display_power_get(dev_priv, POWER_DOMAIN_INIT);
>                 seq_printf(m, "Port hotplug:\t%08x\n",
>                            I915_READ(PORT_HOTPLUG_EN));
>                 seq_printf(m, "DPFLIPSTAT:\t%08x\n",
>                            I915_READ(VLV_DPFLIPSTAT));
>                 seq_printf(m, "DPINVGTT:\t%08x\n",
>                            I915_READ(DPINVGTT));
> +               intel_display_power_put(dev_priv, POWER_DOMAIN_INIT, pref);

Seems reasonable explanation.
Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>

Hopefully, that is enough. If not, we need to ask Imre what the correct
power domain should be :)
-Chris