Re: [RFC 3/8] drm/i915/bxt: Init PPS, Calculate DSI frequency and DPHY parameters for DSC

[vkorjani <vikas.korjani@intel.com>]

On Wednesday 12 August 2015 07:05 PM, Daniel Vetter wrote:
> On Wed, Aug 12, 2015 at 03:23:48PM +0530, vikas.korjani@intel.com wrote:
>> From: vkorjani <vikas.korjani@intel.com>
>>
>> This patch adds code to initialize Picture  Parameter set (PPS)
>> data structure for DSC.
>> DSC is enabled than the bitrate should be calculated using the
>> formula pixel_clock * bits_per_pixel / lane_count, where
>> bits_per_pixel can be 8bpp, 10bpp, 12bpp.
>> value of bits_per_pixel is available in step of 1/16 in
>> pps date structure.
>> DPHY parameters are computed based on data rate calculated
>> as per bits_per_pixel provided in pps data structure.
>>
>> Signed-off-by: vkorjani <vikas.korjani@intel.com>
>> Signed-off-by: Yogesh Mohan Marimuthu <yogesh.mohan.marimuthu@intel.com>
>> ---
>>   drivers/gpu/drm/i915/intel_dsi.h           |    5 +++++
>>   drivers/gpu/drm/i915/intel_dsi_panel_vbt.c |   11 +++++++++++
>>   drivers/gpu/drm/i915/intel_dsi_pll.c       |   24 ++++++++++++++++--------
>>   3 files changed, 32 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/intel_dsi.h b/drivers/gpu/drm/i915/intel_dsi.h
>> index 24fc550..699f995 100644
>> --- a/drivers/gpu/drm/i915/intel_dsi.h
>> +++ b/drivers/gpu/drm/i915/intel_dsi.h
>> @@ -96,6 +96,11 @@ struct intel_dsi {
>>   	u16 panel_on_delay;
>>   	u16 panel_off_delay;
>>   	u16 panel_pwr_cycle_delay;
>> +
>> +	/*DSC Support */
>> +	u8 dsc_enable;
>> +	struct vesa_dsc_pps_data pps_data;
>> +	u8 dsc_bpp;
>>   };
>>   
>>   struct intel_dsi_host {
>> diff --git a/drivers/gpu/drm/i915/intel_dsi_panel_vbt.c b/drivers/gpu/drm/i915/intel_dsi_panel_vbt.c
>> index a5e99ac..f893d37 100644
>> --- a/drivers/gpu/drm/i915/intel_dsi_panel_vbt.c
>> +++ b/drivers/gpu/drm/i915/intel_dsi_panel_vbt.c
>> @@ -413,6 +413,17 @@ struct drm_panel *vbt_panel_init(struct intel_dsi *intel_dsi, u16 panel_id)
>>   		bits_per_pixel = 18;
>>   	else if (intel_dsi->pixel_format == VID_MODE_FORMAT_RGB565)
>>   		bits_per_pixel = 16;
>> +	else if (intel_dsi->pixel_format == VID_MODE_FORMAT_COMPRESSED &&
>> +			dev_priv->vbt.dsc_param.dsc_support) {
>> +		intel_dsi->dsc_enable = true;
>> +		intel_dsi->dsc_bpp =
>> +			(intel_dsi->pps_data.bits_per_pixel / 16);
>> +		bits_per_pixel = intel_dsi->dsc_bpp;
>> +		intel_dsi->pps_data =
>> +			dev_priv->vbt.dsc_param.pps_data;
>> +		/*TODO If PPS not available in VBT compute PPS
>> +		 * from capablity parameter set in vbt */
> We don't seem to feed back the dsi bits_per_pixel information into our
> computation of pipe_config->pipe_bpp. We probably need to fix that to
> actually be able to drive the higher bpc modes ...
>
> Wiring this up correctly should probably be a prep patch.
Yes will fix this.
>
> Also do we have to compute bpp differently for dsc? Can't we just store
> bits_per_pixel somewhere?
> -Daniel
intel_dsi->dsc_bpp stores target bpp after compression.
We can store orginal bpp in intel_dsi->dsi_bpp, some thing similar
is done in this patch

http://lists.freedesktop.org/archives/intel-gfx/2015-May/067627.html
which is still under review.

>
>> +	}
>>   
>>   	intel_dsi->operation_mode = mipi_config->is_cmd_mode;
>>   	intel_dsi->video_mode_format = mipi_config->video_transfer_mode;
>> diff --git a/drivers/gpu/drm/i915/intel_dsi_pll.c b/drivers/gpu/drm/i915/intel_dsi_pll.c
>> index b647f13..38c9433 100644
>> --- a/drivers/gpu/drm/i915/intel_dsi_pll.c
>> +++ b/drivers/gpu/drm/i915/intel_dsi_pll.c
>> @@ -143,10 +143,17 @@ static u32 dsi_rr_formula(const struct drm_display_mode *mode,
>>   #else
>>   
>>   /* Get DSI clock from pixel clock */
>> -static u32 dsi_clk_from_pclk(u32 pclk, int pixel_format, int lane_count)
>> +static u32 dsi_clk_from_pclk(struct intel_encoder *encoder,
>> +			u32 pclk, int pixel_format, int lane_count)
>>   {
>> +	struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);
>>   	u32 dsi_clk_khz;
>> -	u32 bpp = dsi_pixel_format_bpp(pixel_format);
>> +	u32 bpp;
>> +
>> +	if (intel_dsi->dsc_enable)
>> +		bpp =  intel_dsi->dsc_bpp;
>> +	else
>> +		bpp = dsi_pixel_format_bpp(pixel_format);
>>   
>>   	/* DSI data rate = pixel clock * bits per pixel / lane count
>>   	   pixel clock is converted from KHz to Hz */
>> @@ -223,8 +230,8 @@ static void vlv_configure_dsi_pll(struct intel_encoder *encoder)
>>   	struct dsi_mnp dsi_mnp;
>>   	u32 dsi_clk;
>>   
>> -	dsi_clk = dsi_clk_from_pclk(intel_dsi->pclk, intel_dsi->pixel_format,
>> -				    intel_dsi->lane_count);
>> +	dsi_clk = dsi_clk_from_pclk(encoder, intel_dsi->pclk,
>> +			intel_dsi->pixel_format, intel_dsi->lane_count);
>>   
>>   	ret = dsi_calc_mnp(dev_priv, &dsi_mnp, dsi_clk);
>>   	if (ret) {
>> @@ -410,8 +417,9 @@ u32 bxt_get_dsi_pclk(struct intel_encoder *encoder, int pipe_bpp)
>>   
>>   	dsi_clk = (dsi_ratio * BXT_REF_CLOCK_KHZ) / 2;
>>   
>> -	/* pixel_format and pipe_bpp should agree */
>> -	assert_bpp_mismatch(intel_dsi->pixel_format, pipe_bpp);
>> +	/* pixel_format and pipe_bpp should agree if DSC is not enabled */
>> +	if (!intel_dsi->dsc_enable)
>> +		assert_bpp_mismatch(intel_dsi->pixel_format, pipe_bpp);
>>   
>>   	pclk = DIV_ROUND_CLOSEST(dsi_clk * intel_dsi->lane_count, pipe_bpp);
>>   
>> @@ -475,8 +483,8 @@ static bool bxt_configure_dsi_pll(struct intel_encoder *encoder)
>>   	u32 dsi_clk;
>>   	u32 val;
>>   
>> -	dsi_clk = dsi_clk_from_pclk(intel_dsi->pclk, intel_dsi->pixel_format,
>> -			intel_dsi->lane_count);
>> +	dsi_clk = dsi_clk_from_pclk(encoder, intel_dsi->pclk,
>> +			intel_dsi->pixel_format, intel_dsi->lane_count);
>>   
>>   	/*
>>   	 * From clock diagram, to get PLL ratio divider, divide double of DSI
>> -- 
>> 1.7.9.5
>>
>> _______________________________________________
>> Intel-gfx mailing list
>> Intel-gfx@lists.freedesktop.org
>> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

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