Re: [Intel-gfx] [V6 2/9] drm/i915/dsi: Add vblank calculation for command mode

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

On Thu, 09 Jan 2020, Vandita Kulkarni <vandita.kulkarni@intel.com> wrote:
> Transcoder timing calculation differ for command mode.
>
> v2: Use is_vid_mode, and use same I915_WRITE (Jani)
> v3: Adjust the calculations to reflect dsc compression ratio
>
> Signed-off-by: Vandita Kulkarni <vandita.kulkarni@intel.com>
> ---
>  drivers/gpu/drm/i915/display/icl_dsi.c | 52 +++++++++++++++++---------
>  1 file changed, 35 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/icl_dsi.c b/drivers/gpu/drm/i915/display/icl_dsi.c
> index ca37beca3e41..66dc8be672b8 100644
> --- a/drivers/gpu/drm/i915/display/icl_dsi.c
> +++ b/drivers/gpu/drm/i915/display/icl_dsi.c
> @@ -808,9 +808,11 @@ gen11_dsi_set_transcoder_timings(struct intel_encoder *encoder,
>  	enum transcoder dsi_trans;
>  	/* horizontal timings */
>  	u16 htotal, hactive, hsync_start, hsync_end, hsync_size;
> +	u16 cal_htotal, cal_vtotal;

I don't think you actually need these for anything, you can just use
htotal and vtotal directly. This is a function with tons of locals
already, gets confusing.

>  	u16 hback_porch;
>  	/* vertical timings */
>  	u16 vtotal, vactive, vsync_start, vsync_end, vsync_shift;
> +	int bpp, line_time_us, byte_clk_period_ns;

These belong in the if block with smaller scope.

>  	int mul = 1, div = 1;
>  
>  	/*
> @@ -827,14 +829,27 @@ gen11_dsi_set_transcoder_timings(struct intel_encoder *encoder,
>  	}
>  
>  	hactive = adjusted_mode->crtc_hdisplay;
> -	htotal = DIV_ROUND_UP(adjusted_mode->crtc_htotal * mul, div);
> +	vactive = adjusted_mode->crtc_vdisplay;

Please keep the horizontal and vertical timing stuff separate. First
horizontal, then vertical, like they are.

> +	if (is_cmd_mode(intel_dsi)) {
> +		bpp = mipi_dsi_pixel_format_to_bpp(intel_dsi->pixel_format);
> +		byte_clk_period_ns = 8 * 1000000 / intel_dsi->pclk;
> +		cal_htotal = hactive + 160;
> +		line_time_us = (cal_htotal * (bpp / 8) * byte_clk_period_ns) / (1000 * intel_dsi->lane_count);
> +		cal_vtotal = vactive + DIV_ROUND_UP(460, line_time_us);
> +	}
> +
> +	if (is_vid_mode(intel_dsi))
> +		cal_htotal = adjusted_mode->crtc_htotal;

That should be an else branch. Or maybe is_vid_mode() first, and do the
command mode stuff in the else branch.


> +	htotal = DIV_ROUND_UP(cal_htotal * mul, div);
>  	hsync_start = DIV_ROUND_UP(adjusted_mode->crtc_hsync_start * mul, div);
>  	hsync_end = DIV_ROUND_UP(adjusted_mode->crtc_hsync_end * mul, div);
>  	hsync_size  = hsync_end - hsync_start;
>  	hback_porch = (adjusted_mode->crtc_htotal -
>  		       adjusted_mode->crtc_hsync_end);
> -	vactive = adjusted_mode->crtc_vdisplay;
> -	vtotal = adjusted_mode->crtc_vtotal;
> +
> +	if (is_vid_mode(intel_dsi))
> +		cal_vtotal = adjusted_mode->crtc_vtotal;
> +	vtotal = cal_vtotal;

This would make more sense if the command mode vtotal stuff was done
here instead of in the middle of the horizontal timings.

>  	vsync_start = adjusted_mode->crtc_vsync_start;
>  	vsync_end = adjusted_mode->crtc_vsync_end;
>  	vsync_shift = hsync_start - htotal / 2;
> @@ -862,7 +877,7 @@ gen11_dsi_set_transcoder_timings(struct intel_encoder *encoder,
>  	}
>  
>  	/* TRANS_HSYNC register to be programmed only for video mode */
> -	if (intel_dsi->operation_mode == INTEL_DSI_VIDEO_MODE) {
> +	if (is_vid_mode(intel_dsi)) {
>  		if (intel_dsi->video_mode_format ==
>  		    VIDEO_MODE_NON_BURST_WITH_SYNC_PULSE) {
>  			/* BSPEC: hsync size should be atleast 16 pixels */
> @@ -885,13 +900,12 @@ gen11_dsi_set_transcoder_timings(struct intel_encoder *encoder,
>  		}
>  	}
>  
> -	/* program TRANS_VTOTAL register */
>  	for_each_dsi_port(port, intel_dsi->ports) {
>  		dsi_trans = dsi_port_to_transcoder(port);
>  		/*
> -		 * FIXME: Programing this by assuming progressive mode, since
> -		 * non-interlaced info from VBT is not saved inside
> -		 * struct drm_display_mode.
> +		 * FIXME: Programing this by assuming progressive mode,
> +		 * since non-interlaced info from VBT is not saved
> +		 * inside struct drm_display_mode.
>  		 * For interlace mode: program required pixel minus 2
>  		 */
>  		I915_WRITE(VTOTAL(dsi_trans),
> @@ -904,22 +918,26 @@ gen11_dsi_set_transcoder_timings(struct intel_encoder *encoder,
>  	if (vsync_start < vactive)
>  		DRM_ERROR("vsync_start less than vactive\n");
>  
> -	/* program TRANS_VSYNC register */
> -	for_each_dsi_port(port, intel_dsi->ports) {
> -		dsi_trans = dsi_port_to_transcoder(port);
> -		I915_WRITE(VSYNC(dsi_trans),
> -			   (vsync_start - 1) | ((vsync_end - 1) << 16));
> +	/* program TRANS_VSYNC register for video mode only */
> +	if (is_vid_mode(intel_dsi)) {
> +		for_each_dsi_port(port, intel_dsi->ports) {
> +			dsi_trans = dsi_port_to_transcoder(port);
> +			I915_WRITE(VSYNC(dsi_trans),
> +				   (vsync_start - 1) | ((vsync_end - 1) << 16));
> +		}
>  	}
>  
>  	/*
> -	 * FIXME: It has to be programmed only for interlaced
> +	 * FIXME: It has to be programmed only for video modes and interlaced
>  	 * modes. Put the check condition here once interlaced
>  	 * info available as described above.
>  	 * program TRANS_VSYNCSHIFT register
>  	 */
> -	for_each_dsi_port(port, intel_dsi->ports) {
> -		dsi_trans = dsi_port_to_transcoder(port);
> -		I915_WRITE(VSYNCSHIFT(dsi_trans), vsync_shift);
> +	if (is_vid_mode(intel_dsi)) {
> +		for_each_dsi_port(port, intel_dsi->ports) {
> +			dsi_trans = dsi_port_to_transcoder(port);
> +			I915_WRITE(VSYNCSHIFT(dsi_trans), vsync_shift);
> +		}
>  	}
>  
>  	/* program TRANS_VBLANK register, should be same as vtotal programmed */

-- 
Jani Nikula, Intel Open Source Graphics Center
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