> -Original Message-
> From: Nautiyal, Ankit K
> Sent: Monday, August 2, 2021 6:27 PM
> To: intel-gfx@lists.freedesktop.org
> Cc: Shankar, Uma ; Zanoni, Paulo R
> ; ville.syrj...@linux.intel.com;
> daniel.vet...@ffwll.ch;
> jani.nik...@linux.intel.com; joonas.lahti...@linux.intel.com; Vivi, Rodrigo
> ; sta...@vger.kernel.org
> Subject: [PATCH v2] drm/i915/display: Fix the 12 BPC bits for PIPE_MISC reg
>
> From: Ankit Nautiyal
>
> Till DISPLAY12 the PIPE_MISC bits 5-7 are used to set the Dithering BPC, with
> valid
> values of 6, 8, 10 BPC, with Dithering bit enabled.
> Also, these bits are used in case of HW readout for pipe_bpp in case of DSI.
> For ADLP+ these bits are used to set the PORT OUTPUT BPC, with valid values
> of: 6,
> 8, 10, 12 BPC, and need to be programmed whether dithering is enabled or not.
>
> This patch:
> -corrects the bits 5-7 for PIPE MISC register for 12 BPC.
> -renames the bits and mask to have generic names for these bits for dithering
> bpc
> and port output bpc.
>
> v2: Addressed the comments and suggestions from Uma Shankar:
> -Add 'display' in subject
> -Add Fixes tag in the commit message.
> -Take care of DSI case which uses the bits for getting pipe_bpp.
>
> Fixes: 756f85cffef2 ("drm/i915/bdw: Broadwell has PIPEMISC")
> Cc: Paulo Zanoni (v1)
> Cc: Ville Syrjälä
> Cc: Daniel Vetter
> Cc: Jani Nikula
> Cc: Joonas Lahtinen
> Cc: Rodrigo Vivi
> Cc: intel-gfx@lists.freedesktop.org
> Cc: # v3.13+
>
> Signed-off-by: Ankit Nautiyal
> ---
> drivers/gpu/drm/i915/display/intel_display.c | 18 +-
> drivers/gpu/drm/i915/i915_reg.h | 15 ++-
> 2 files changed, 19 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_display.c
> b/drivers/gpu/drm/i915/display/intel_display.c
> index 65ddb6c..9766b36 100644
> --- a/drivers/gpu/drm/i915/display/intel_display.c
> +++ b/drivers/gpu/drm/i915/display/intel_display.c
> @@ -5760,16 +5760,16 @@ static void bdw_set_pipemisc(const struct
> intel_crtc_state *crtc_state)
>
> switch (crtc_state->pipe_bpp) {
> case 18:
> - val |= PIPEMISC_DITHER_6_BPC;
> + val |= PIPEMISC_6_BPC;
> break;
> case 24:
> - val |= PIPEMISC_DITHER_8_BPC;
> + val |= PIPEMISC_8_BPC;
> break;
> case 30:
> - val |= PIPEMISC_DITHER_10_BPC;
> + val |= PIPEMISC_10_BPC;
> break;
> case 36:
> - val |= PIPEMISC_DITHER_12_BPC;
> + val |= PIPEMISC_12_BPC;
Isn't this bit not supported on prior to Gen13 platforms, so from that
perspective it's an
Invalid operation. Can you confirm.
> break;
> default:
> MISSING_CASE(crtc_state->pipe_bpp);
> @@ -5822,14 +5822,14 @@ int bdw_get_pipemisc_bpp(struct intel_crtc *crtc)
>
> tmp = intel_de_read(dev_priv, PIPEMISC(crtc->pipe));
>
> - switch (tmp & PIPEMISC_DITHER_BPC_MASK) {
> - case PIPEMISC_DITHER_6_BPC:
> + switch (tmp & PIPEMISC_BPC_MASK) {
> + case PIPEMISC_6_BPC:
> return 18;
> - case PIPEMISC_DITHER_8_BPC:
> + case PIPEMISC_8_BPC:
> return 24;
> - case PIPEMISC_DITHER_10_BPC:
> + case PIPEMISC_10_BPC:
> return 30;
> - case PIPEMISC_DITHER_12_BPC:
> + case PIPEMISC_12_BPC:
> return 36;
Same here.
> default:
> MISSING_CASE(tmp);
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index 943fe48..bbfe4f4 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -6166,11 +6166,16 @@ enum {
> #define PIPEMISC_HDR_MODE_PRECISION(1 << 23) /* icl+ */
> #define PIPEMISC_OUTPUT_COLORSPACE_YUV (1 << 11)
> #define PIPEMISC_PIXEL_ROUNDING_TRUNC REG_BIT(8) /* tgl+ */
> -#define PIPEMISC_DITHER_BPC_MASK (7 << 5)
> -#define PIPEMISC_DITHER_8_BPC (0 << 5)
> -#define PIPEMISC_DITHER_10_BPC (1 << 5)
> -#define PIPEMISC_DITHER_6_BPC (2 << 5)
> -#define PIPEMISC_DITHER_12_BPC (3 << 5)
> +/*
> + * For Display < 13, Bits 5-7 of PIPE MISC represent DITHER BPC.
> + * ADLP+, the bits 5-7 represent PORT OUTPUT BPC with valid values of:
> + * 6, 8, 10, 12 BPC.
> + */
> +#define PIPEMISC_BPC_MASK (7 << 5)
> +#define PIPEMISC_8_BPC (0 << 5)
> +#define PIPEMISC_10_BPC(1 << 5)
> +#define PIPEMISC_6_BPC (2 << 5)
> +#define PIPEMISC_12_BPC(4 << 5) /* adlp+ */
> #define PIPEMISC_DITHER_ENABLE (1 << 4)
> #define PIPEMISC_DITHER_TYPE_MASK (3 << 2)
> #define PIPEMISC_DITHER_TYPE_SP(0 << 2)
> --
> 2.8.1
