Re: [Freedreno] [REPOST PATCH v4 13/13] drm/msm/dsi: Add support for DSC configuration

[Vinod Koul <vkoul@kernel.org>]

On 16-02-22, 19:44, Abhinav Kumar wrote:
> 
> 
> On 2/10/2022 2:34 AM, Vinod Koul wrote:
> > When DSC is enabled, we need to configure DSI registers accordingly and
> > configure the respective stream compression registers.
> > 
> > Add support to calculate the register setting based on DSC params and
> > timing information and configure these registers.
> > 
> > Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> > Signed-off-by: Vinod Koul <vkoul@kernel.org>
> > ---
> >   drivers/gpu/drm/msm/dsi/dsi.xml.h  |  10 +++
> >   drivers/gpu/drm/msm/dsi/dsi_host.c | 109 ++++++++++++++++++++++++++++-
> >   2 files changed, 118 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/gpu/drm/msm/dsi/dsi.xml.h b/drivers/gpu/drm/msm/dsi/dsi.xml.h
> > index 49b551ad1bff..c1c85df58c4b 100644
> > --- a/drivers/gpu/drm/msm/dsi/dsi.xml.h
> > +++ b/drivers/gpu/drm/msm/dsi/dsi.xml.h
> > @@ -706,4 +706,14 @@ static inline uint32_t DSI_VERSION_MAJOR(uint32_t val)
> >   #define REG_DSI_CPHY_MODE_CTRL					0x000002d4
> > +#define REG_DSI_VIDEO_COMPRESSION_MODE_CTRL			0x0000029c
> > +
> > +#define REG_DSI_VIDEO_COMPRESSION_MODE_CTRL2			0x000002a0
> > +
> > +#define REG_DSI_COMMAND_COMPRESSION_MODE_CTRL			0x000002a4
> > +
> > +#define REG_DSI_COMMAND_COMPRESSION_MODE_CTRL2			0x000002a8
> > +
> > +#define REG_DSI_COMMAND_COMPRESSION_MODE_CTRL3			0x000002ac
> > +
> 
> This file should not be edited manually. The updates have to be generated
> using the headergen tool.

I have already send mesa patch for that. https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/14967#note_1253974
You should chime in there as well :)

I will split these and get these generated one as a separate patch..


> 
> >   #endif /* DSI_XML */
> > diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
> > index 438c80750682..3d8d5a1daaa3 100644
> > --- a/drivers/gpu/drm/msm/dsi/dsi_host.c
> > +++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
> > @@ -908,6 +908,20 @@ static void dsi_ctrl_config(struct msm_dsi_host *msm_host, bool enable,
> >   		dsi_write(msm_host, REG_DSI_CPHY_MODE_CTRL, BIT(0));
> >   }
> > +static int dsi_dsc_update_pic_dim(struct msm_display_dsc_config *dsc,
> > +				  int pic_width, int pic_height)
> > +{
> > +	if (!dsc || !pic_width || !pic_height) {
> > +		pr_err("DSI: invalid input: pic_width: %d pic_height: %d\n", pic_width, pic_height);
> > +		return -EINVAL;
> > +	}
> > +
> > +	dsc->drm->pic_width = pic_width;
> > +	dsc->drm->pic_height = pic_height;
> > +
> > +	return 0;
> > +}
> > +
> >   static void dsi_timing_setup(struct msm_dsi_host *msm_host, bool is_bonded_dsi)
> >   {
> >   	struct drm_display_mode *mode = msm_host->mode;
> > @@ -940,7 +954,68 @@ static void dsi_timing_setup(struct msm_dsi_host *msm_host, bool is_bonded_dsi)
> >   		hdisplay /= 2;
> >   	}
> > +	if (msm_host->dsc) {
> > +		struct msm_display_dsc_config *dsc = msm_host->dsc;
> > +
> > +		/* update dsc params with timing params */
> > +		dsi_dsc_update_pic_dim(dsc, mode->hdisplay, mode->vdisplay);
> > +		DBG("Mode Width- %d x Height %d\n", dsc->drm->pic_width, dsc->drm->pic_height);
> > +
> > +		/* we do the calculations for dsc parameters here so that
> > +		 * panel can use these parameters
> > +		 */
> > +		dsi_populate_dsc_params(dsc);
> > +
> > +		/* Divide the display by 3 but keep back/font porch and
> > +		 * pulse width same
> > +		 */
> > +		h_total -= hdisplay;
> > +		hdisplay /= 3;
> > +		h_total += hdisplay;
> > +		ha_end = ha_start + hdisplay;
> > +	}
> > +
> >   	if (msm_host->mode_flags & MIPI_DSI_MODE_VIDEO) {
> > +		if (msm_host->dsc) {
> > +			struct msm_display_dsc_config *dsc = msm_host->dsc;
> > +			u32 reg, intf_width, slice_per_intf;
> > +			u32 total_bytes_per_intf;
> > +
> > +			/* first calculate dsc parameters and then program
> > +			 * compress mode registers
> > +			 */
> > +			intf_width = hdisplay;
> > +			slice_per_intf = DIV_ROUND_UP(intf_width, dsc->drm->slice_width);
> > +
> > +			dsc->drm->slice_count = 1;
> 
> Why is this hard-coded to 1 here? Am i missing something?
> I think I need another day to look into these calculations.

Thanks for spotting this, it should be:
                        dsc->drm->slice_count = DIV_ROUND_UP(intf_width, dsc->drm->slice_widths);

which is slice_per_intf so I will update this

-- 
~Vinod