On Thu, 04 Dec 2014, Gaurav K Singh <gaurav.k.si...@intel.com> wrote:
> For dual link MIPI Panels, each port needs half of pixel clock. Pixel overlap
> can be enabled if needed by panel, then in that case, pixel clock will be
> increased for extra pixels.
>
> v2 : Address review comments by Jani
>      - Removed the bit mask used for ->dual_link
>      - Used DSI instead of MIPI for #define variables
>
> Signed-off-by: Gaurav K Singh <gaurav.k.si...@intel.com>
> ---
>  drivers/gpu/drm/i915/i915_reg.h            |    4 ++++
>  drivers/gpu/drm/i915/intel_bios.h          |    3 ++-
>  drivers/gpu/drm/i915/intel_dsi.c           |    8 ++++++++
>  drivers/gpu/drm/i915/intel_dsi.h           |    6 ++++++
>  drivers/gpu/drm/i915/intel_dsi_panel_vbt.c |   21 +++++++++++++++++++++
>  5 files changed, 41 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index c981f5d..87149ba 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -6029,6 +6029,10 @@ enum punit_power_well {
>  #define GEN8_PMINTR_REDIRECT_TO_NON_DISP     (1<<31)
>  #define VLV_PWRDWNUPCTL                              0xA294
>  
> +#define VLV_CHICKEN_3                                0x7040C
> +#define  PIXEL_OVERLAP_CNT_MASK                      (3 << 30)
> +#define  PIXEL_OVERLAP_CNT_SHIFT             30

I didn't find this register, but does it not need + VLV_DISPLAY_BASE?

Given that I can't find the register my review is pretty shallow, but I
don't spot anything obviously wrong either. With these caveats,

Reviewed-by: Jani Nikula <jani.nik...@intel.com>


> +
>  #define GEN6_PMISR                           0x44020
>  #define GEN6_PMIMR                           0x44024 /* rps_lock */
>  #define GEN6_PMIIR                           0x44028
> diff --git a/drivers/gpu/drm/i915/intel_bios.h 
> b/drivers/gpu/drm/i915/intel_bios.h
> index de01167..a6a8710 100644
> --- a/drivers/gpu/drm/i915/intel_bios.h
> +++ b/drivers/gpu/drm/i915/intel_bios.h
> @@ -818,7 +818,8 @@ struct mipi_config {
>  #define DUAL_LINK_PIXEL_ALT  2
>       u16 dual_link:2;
>       u16 lane_cnt:2;
> -     u16 rsvd3:12;
> +     u16 pixel_overlap:3;
> +     u16 rsvd3:9;
>  
>       u16 rsvd4;
>  
> diff --git a/drivers/gpu/drm/i915/intel_dsi.c 
> b/drivers/gpu/drm/i915/intel_dsi.c
> index dbe52e9..4e18abd 100644
> --- a/drivers/gpu/drm/i915/intel_dsi.c
> +++ b/drivers/gpu/drm/i915/intel_dsi.c
> @@ -111,6 +111,14 @@ static void intel_dsi_port_enable(struct intel_encoder 
> *encoder)
>       enum port port;
>       u32 temp;
>  
> +     if (intel_dsi->dual_link == DSI_DUAL_LINK_FRONT_BACK) {
> +             temp = I915_READ(VLV_CHICKEN_3);
> +             temp &= ~PIXEL_OVERLAP_CNT_MASK |
> +                                     intel_dsi->pixel_overlap <<
> +                                     PIXEL_OVERLAP_CNT_SHIFT;
> +             I915_WRITE(VLV_CHICKEN_3, temp);
> +     }
> +
>       for_each_dsi_port(port, intel_dsi->ports) {
>               temp = I915_READ(MIPI_PORT_CTRL(port));
>  
> diff --git a/drivers/gpu/drm/i915/intel_dsi.h 
> b/drivers/gpu/drm/i915/intel_dsi.h
> index f2cc2fc..8fe2064 100644
> --- a/drivers/gpu/drm/i915/intel_dsi.h
> +++ b/drivers/gpu/drm/i915/intel_dsi.h
> @@ -28,6 +28,11 @@
>  #include <drm/drm_crtc.h>
>  #include "intel_drv.h"
>  
> +/* Dual Link support */
> +#define DSI_DUAL_LINK_NONE           0
> +#define DSI_DUAL_LINK_FRONT_BACK     1
> +#define DSI_DUAL_LINK_PIXEL_ALT              2
> +
>  struct intel_dsi_device {
>       unsigned int panel_id;
>       const char *name;
> @@ -105,6 +110,7 @@ struct intel_dsi {
>  
>       u8 escape_clk_div;
>       u8 dual_link;
> +     u8 pixel_overlap;
>       u32 port_bits;
>       u32 bw_timer;
>       u32 dphy_reg;
> diff --git a/drivers/gpu/drm/i915/intel_dsi_panel_vbt.c 
> b/drivers/gpu/drm/i915/intel_dsi_panel_vbt.c
> index f60146f..f8c2269 100644
> --- a/drivers/gpu/drm/i915/intel_dsi_panel_vbt.c
> +++ b/drivers/gpu/drm/i915/intel_dsi_panel_vbt.c
> @@ -288,6 +288,7 @@ static bool generic_init(struct intel_dsi_device *dsi)
>       intel_dsi->lane_count = mipi_config->lane_cnt + 1;
>       intel_dsi->pixel_format = mipi_config->videomode_color_format << 7;
>       intel_dsi->dual_link = mipi_config->dual_link;
> +     intel_dsi->pixel_overlap = mipi_config->pixel_overlap;
>  
>       if (intel_dsi->dual_link)
>               intel_dsi->ports = ((1 << PORT_A) | (1 << PORT_C));
> @@ -310,6 +311,20 @@ static bool generic_init(struct intel_dsi_device *dsi)
>  
>       pclk = mode->clock;
>  
> +     /* In dual link mode each port needs half of pixel clock */
> +     if (intel_dsi->dual_link) {
> +             pclk = pclk / 2;
> +
> +             /* we can enable pixel_overlap if needed by panel. In this
> +              * case we need to increase the pixelclock for extra pixels
> +              */
> +             if (intel_dsi->dual_link == DSI_DUAL_LINK_FRONT_BACK) {
> +                     pclk += DIV_ROUND_UP(mode->vtotal *
> +                                             intel_dsi->pixel_overlap *
> +                                             60, 1000);
> +             }
> +     }
> +
>       /* Burst Mode Ratio
>        * Target ddr frequency from VBT / non burst ddr freq
>        * multiply by 100 to preserve remainder
> @@ -504,6 +519,12 @@ static bool generic_init(struct intel_dsi_device *dsi)
>       DRM_DEBUG_KMS("Clockstop %s\n", intel_dsi->clock_stop ?
>                                               "disabled" : "enabled");
>       DRM_DEBUG_KMS("Mode %s\n", intel_dsi->operation_mode ? "command" : 
> "video");
> +     if (intel_dsi->dual_link == DSI_DUAL_LINK_FRONT_BACK)
> +             DRM_DEBUG_KMS("Dual link: DSI_DUAL_LINK_FRONT_BACK\n");
> +     else if (intel_dsi->dual_link == DSI_DUAL_LINK_PIXEL_ALT)
> +             DRM_DEBUG_KMS("Dual link: DSI_DUAL_LINK_PIXEL_ALT\n");
> +     else
> +             DRM_DEBUG_KMS("Dual link: NONE\n");
>       DRM_DEBUG_KMS("Pixel Format %d\n", intel_dsi->pixel_format);
>       DRM_DEBUG_KMS("TLPX %d\n", intel_dsi->escape_clk_div);
>       DRM_DEBUG_KMS("LP RX Timeout 0x%x\n", intel_dsi->lp_rx_timeout);
> -- 
> 1.7.9.5
>
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-- 
Jani Nikula, Intel Open Source Technology Center
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