Re: [PATCH] i915: Expose panel power cycle delay to i915_panel_timings

From: Jani Nikula <jani.nikula@linux.intel.com>
To: Anshuamn Gupta <anshuman.gupta@intel.com>
Cc: intel-gfx@lists.freedesktop.org
Subject: Re: [PATCH] i915: Expose panel power cycle delay to i915_panel_timings
Date: Tue, 03 Dec 2019 09:59:54 +0200	[thread overview]
Message-ID: <87pnh5kfet.fsf@intel.com> (raw)
In-Reply-To: <20191203061315.GA8432@intel.com>

On Tue, 03 Dec 2019, Anshuamn Gupta <anshuman.gupta@intel.com> wrote:
> On 2019-11-28 at 16:05:03 +0200, Jani Nikula wrote:
>> On Mon, 18 Nov 2019, Anshuman Gupta <anshuman.gupta@intel.com> wrote:
>> > Putting down the AUX power domain reference count in
>> > edp vdd off async sequence takes too much of time
>> > (relative to panel power cycle delay) therefore it make sense
>> > to expose the panel power cycle delay to i915_panel_timings
>> > along with other delays.
>> > It can be use by DC state IGT to wait for strict power cycle delay
>> > in order to check for various DC state counters.
>> 
>> Catching up on review, are you suggesting to look at this kind of
>> debugfs files for tests? Please find another way.
> Actually on few panels power cycle delay is too much that it is required 
> to wait for 6 seconds in igt for an timeout, but this could really affect
> CI execution time on panel with lesser power cycle delay.
> (https://patchwork.freedesktop.org/series/68478/)
> For this specific reason i thought it may be good to expose
> panel power cycle delay with other panel delay and use that
> in igt.

Fix the kernel driver to DTRT instead of exposing the guts and having
igt work around it.

BR,
Jani.

> Thanks ,
> Anshuman.
>> 
>> I don't mind having the debugfs info per se.
>> 
>> BR,
>> Jani.
>> 
>> >
>> > Cc: Imre Deak <imre.deak@intel.com>
>> > Signed-off-by: Anshuman Gupta <anshuman.gupta@intel.com>
>> > ---
>> >  drivers/gpu/drm/i915/i915_debugfs.c | 2 ++
>> >  1 file changed, 2 insertions(+)
>> >
>> > diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
>> > index cab632791f73..c075cc2b7bb5 100644
>> > --- a/drivers/gpu/drm/i915/i915_debugfs.c
>> > +++ b/drivers/gpu/drm/i915/i915_debugfs.c
>> > @@ -4436,6 +4436,8 @@ static int i915_panel_show(struct seq_file *m, void *data)
>> >  		   intel_dp->panel_power_up_delay);
>> >  	seq_printf(m, "Panel power down delay: %d\n",
>> >  		   intel_dp->panel_power_down_delay);
>> > +	seq_printf(m, "Panel power cycle delay: %d\n",
>> > +		   intel_dp->panel_power_cycle_delay);
>> >  	seq_printf(m, "Backlight on delay: %d\n",
>> >  		   intel_dp->backlight_on_delay);
>> >  	seq_printf(m, "Backlight off delay: %d\n",
>> 
>> -- 
>> Jani Nikula, Intel Open Source Graphics Center

-- 
Jani Nikula, Intel Open Source Graphics Center
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