Re: [PATCH 09/18] drm/i915/dsi: Make intel_dsi_enable/disable directly exec VBT sequences

[Jani Nikula <jani.nikula@linux.intel.com>]

On Fri, 02 Dec 2016, Hans de Goede <hdegoede@redhat.com> wrote:
> Hi,
>
> On 02-12-16 11:31, Jani Nikula wrote:
>> On Thu, 01 Dec 2016, Hans de Goede <hdegoede@redhat.com> wrote:
>>> The drm_panel_enable/disable and drm_panel_prepare/unprepare calls are
>>> not fine grained enough to abstract all the different steps we need to
>>> take (and VBT sequences we need to exec) properly. So simply remove the
>>> panel _enable/disable and prepare/unprepare callbacks and instead
>>> export intel_dsi_exec_vbt_sequence() from intel_dsi_panel_vbt.c
>>> and call that from intel_dsi_enable/disable().
>>>
>>> No functional changes.
>>
>> No functional changes, but this is quite a big design change between
>> intel_dsi.c and intel_dsi_panel_vbt.c.
>
> True, I did this because adding a callback per init step to the
> drm_panel interface felt like it will result in a game of
> whack a mole (adding more and more callbacks). See the end of
> this mail for a proposal with leaves the drm_panel interface
> in place, while also avoiding this problem.
>
>> Originally the idea was to
>> separate the dsi core code and the panel specific code, letting one
>> write a panel driver that was not based on values in VBT. This patch
>> changes that.
>
> I see, I was not aware of this history.
>
>> Now I'm not sure if there'll ever be a panel driver not based on VBT,
>> and perhaps the current drm_panel based interface between two is not
>> enough in the end, nor prettiest. But after this patch, we might just as
>> well throw out the drm_panel interface, and refactor the division
>> between the two files completely. Indeed, if we accept the direction set
>> in this patch, that refactoring would be the logical next step.
>
> Is intel_dsi.c the only user of the drm_panel interface ? The name
> suggests it is not intel specific.

Just a quick note here, it's not i915 specific, it's used in other
drivers.

BR,
Jani.

>
>> I have not made up my mind about this yet. An alternative would be to
>> amend the drm_panel interface to achieve the kind of granularity you're
>> after in the follow-up patches. Indeed, such patches have been sent in
>> the past.
>
> How about we add a "drm_panel_exec_sequence" callback to the
> drm_panel interface, which takes an enum argument which (de)init
> step to do ?
>
> Then we can easily add extra init steps later by extending the
> enum, and panel implementations which do not care about certain
> steps can simply treat these as nops. This avoids the need
> to add a ton of callbacks to the drm_panel struct.
>
> If there are no other users, we could then also remove the
> enable/disable and prepare/unprepare pairs from drm_panel
> now, I left those in place assuming that intel_dsi.c was
> not the only user of drm_panel.
>
> Regards,
>
> Hans
>
>
>
>
>>
>> BR,
>> Jani.
>>
>>>
>>> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
>>> ---
>>>  drivers/gpu/drm/i915/intel_dsi.c           | 14 +++++++---
>>>  drivers/gpu/drm/i915/intel_dsi.h           |  3 +++
>>>  drivers/gpu/drm/i915/intel_dsi_panel_vbt.c | 43 ++----------------------------
>>>  3 files changed, 15 insertions(+), 45 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/i915/intel_dsi.c b/drivers/gpu/drm/i915/intel_dsi.c
>>> index 85b748d..cf761e8 100644
>>> --- a/drivers/gpu/drm/i915/intel_dsi.c
>>> +++ b/drivers/gpu/drm/i915/intel_dsi.c
>>> @@ -656,7 +656,10 @@ static void intel_dsi_pre_enable(struct intel_encoder *encoder,
>>>  	/* put device in ready state */
>>>  	intel_dsi_device_ready(encoder);
>>>
>>> -	drm_panel_prepare(intel_dsi->panel);
>>> +	intel_dsi_exec_vbt_sequence(intel_dsi, MIPI_SEQ_ASSERT_RESET);
>>> +	intel_dsi_exec_vbt_sequence(intel_dsi, MIPI_SEQ_POWER_ON);
>>> +	intel_dsi_exec_vbt_sequence(intel_dsi, MIPI_SEQ_DEASSERT_RESET);
>>> +	intel_dsi_exec_vbt_sequence(intel_dsi, MIPI_SEQ_INIT_OTP);
>>>
>>>  	/* Enable port in pre-enable phase itself because as per hw team
>>>  	 * recommendation, port should be enabled befor plane & pipe */
>>> @@ -669,7 +672,8 @@ static void intel_dsi_pre_enable(struct intel_encoder *encoder,
>>>  			dpi_send_cmd(intel_dsi, TURN_ON, false, port);
>>>  		msleep(100);
>>>
>>> -		drm_panel_enable(intel_dsi->panel);
>>> +		intel_dsi_exec_vbt_sequence(intel_dsi, MIPI_SEQ_DISPLAY_ON);
>>> +		intel_dsi_exec_vbt_sequence(intel_dsi, MIPI_SEQ_BACKLIGHT_ON);
>>>
>>>  		intel_dsi_port_enable(encoder);
>>>  	}
>>> @@ -732,7 +736,8 @@ static void intel_dsi_post_disable(struct intel_encoder *encoder,
>>>  	 * if disable packets are sent before sending shutdown packet then in
>>>  	 * some next enable sequence send turn on packet error is observed
>>>  	 */
>>> -	drm_panel_disable(intel_dsi->panel);
>>> +	intel_dsi_exec_vbt_sequence(intel_dsi, MIPI_SEQ_BACKLIGHT_OFF);
>>> +	intel_dsi_exec_vbt_sequence(intel_dsi, MIPI_SEQ_DISPLAY_OFF);
>>>
>>>  	intel_dsi_clear_device_ready(encoder);
>>>
>>> @@ -746,7 +751,8 @@ static void intel_dsi_post_disable(struct intel_encoder *encoder,
>>>  		I915_WRITE(DSPCLK_GATE_D, val);
>>>  	}
>>>
>>> -	drm_panel_unprepare(intel_dsi->panel);
>>> +	intel_dsi_exec_vbt_sequence(intel_dsi, MIPI_SEQ_ASSERT_RESET);
>>> +	intel_dsi_exec_vbt_sequence(intel_dsi, MIPI_SEQ_POWER_OFF);
>>>
>>>  	msleep(intel_dsi->panel_off_delay);
>>>
>>> diff --git a/drivers/gpu/drm/i915/intel_dsi.h b/drivers/gpu/drm/i915/intel_dsi.h
>>> index d567823..5486491 100644
>>> --- a/drivers/gpu/drm/i915/intel_dsi.h
>>> +++ b/drivers/gpu/drm/i915/intel_dsi.h
>>> @@ -132,6 +132,9 @@ static inline struct intel_dsi *enc_to_intel_dsi(struct drm_encoder *encoder)
>>>
>>>  void wait_for_dsi_fifo_empty(struct intel_dsi *intel_dsi, enum port port);
>>>
>>> +void intel_dsi_exec_vbt_sequence(struct intel_dsi *intel_dsi,
>>> +				 enum mipi_seq seq_id);
>>> +
>>>  bool intel_dsi_pll_is_enabled(struct drm_i915_private *dev_priv);
>>>  int intel_compute_dsi_pll(struct intel_encoder *encoder,
>>>  			  struct intel_crtc_state *config);
>>> diff --git a/drivers/gpu/drm/i915/intel_dsi_panel_vbt.c b/drivers/gpu/drm/i915/intel_dsi_panel_vbt.c
>>> index b5a02c6..f71f913 100644
>>> --- a/drivers/gpu/drm/i915/intel_dsi_panel_vbt.c
>>> +++ b/drivers/gpu/drm/i915/intel_dsi_panel_vbt.c
>>> @@ -400,10 +400,9 @@ static const char *sequence_name(enum mipi_seq seq_id)
>>>  		return "(unknown)";
>>>  }
>>>
>>> -static void generic_exec_sequence(struct drm_panel *panel, enum mipi_seq seq_id)
>>> +void intel_dsi_exec_vbt_sequence(struct intel_dsi *intel_dsi,
>>> +				 enum mipi_seq seq_id)
>>>  {
>>> -	struct vbt_panel *vbt_panel = to_vbt_panel(panel);
>>> -	struct intel_dsi *intel_dsi = vbt_panel->intel_dsi;
>>>  	struct drm_i915_private *dev_priv = to_i915(intel_dsi->base.base.dev);
>>>  	const u8 *data;
>>>  	fn_mipi_elem_exec mipi_elem_exec;
>>> @@ -467,40 +466,6 @@ static void generic_exec_sequence(struct drm_panel *panel, enum mipi_seq seq_id)
>>>  	}
>>>  }
>>>
>>> -static int vbt_panel_prepare(struct drm_panel *panel)
>>> -{
>>> -	generic_exec_sequence(panel, MIPI_SEQ_ASSERT_RESET);
>>> -	generic_exec_sequence(panel, MIPI_SEQ_POWER_ON);
>>> -	generic_exec_sequence(panel, MIPI_SEQ_DEASSERT_RESET);
>>> -	generic_exec_sequence(panel, MIPI_SEQ_INIT_OTP);
>>> -
>>> -	return 0;
>>> -}
>>> -
>>> -static int vbt_panel_unprepare(struct drm_panel *panel)
>>> -{
>>> -	generic_exec_sequence(panel, MIPI_SEQ_ASSERT_RESET);
>>> -	generic_exec_sequence(panel, MIPI_SEQ_POWER_OFF);
>>> -
>>> -	return 0;
>>> -}
>>> -
>>> -static int vbt_panel_enable(struct drm_panel *panel)
>>> -{
>>> -	generic_exec_sequence(panel, MIPI_SEQ_DISPLAY_ON);
>>> -	generic_exec_sequence(panel, MIPI_SEQ_BACKLIGHT_ON);
>>> -
>>> -	return 0;
>>> -}
>>> -
>>> -static int vbt_panel_disable(struct drm_panel *panel)
>>> -{
>>> -	generic_exec_sequence(panel, MIPI_SEQ_BACKLIGHT_OFF);
>>> -	generic_exec_sequence(panel, MIPI_SEQ_DISPLAY_OFF);
>>> -
>>> -	return 0;
>>> -}
>>> -
>>>  static int vbt_panel_get_modes(struct drm_panel *panel)
>>>  {
>>>  	struct vbt_panel *vbt_panel = to_vbt_panel(panel);
>>> @@ -524,10 +489,6 @@ static int vbt_panel_get_modes(struct drm_panel *panel)
>>>  }
>>>
>>>  static const struct drm_panel_funcs vbt_panel_funcs = {
>>> -	.disable = vbt_panel_disable,
>>> -	.unprepare = vbt_panel_unprepare,
>>> -	.prepare = vbt_panel_prepare,
>>> -	.enable = vbt_panel_enable,
>>>  	.get_modes = vbt_panel_get_modes,
>>>  };
>>

-- 
Jani Nikula, Intel Open Source Technology Center
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