There are 3 problems with the dsi code's pipe_bpp handling for 6 bpc
pixel-formats which this commit addresses:
1) It assumes that the pipe_bpp is the same as the bpp going over the dsi
lanes. This assumption is not valid for MIPI_DSI_FMT_RGB666, where pipe_bpp
should be 18 so that we do proper dithering but we actually send 24 bpp
over the dsi lanes (MIPI_DSI_FMT_RGB666_PACKED sends 18 bpp).
This assumption is enforced by an assert in *_dsi_get_pclk(). This assert
triggers on the initial hw-state readback on BYT/CHT devices which use
MIPI_DSI_FMT_RGB666, such as the Prowise PT301 tablet. PIPECONF is set to
6BPC / 18 bpp by the GOP, while mipi_dsi_pixel_format_to_bpp() returns 24.
This commits switches the calculations in *_dsi_get_pclk() to use the bpp
from mipi_dsi_pixel_format_to_bpp(intel_dsi->pixel_format) which
returns the bpp going over the mipi lanes and drops the assert.
2) On BXT bxt_dsi_get_pipe_config() wrongly overrides the pipe_bpp which
i9xx_get_pipe_config() reads from PIPECONF with the return value from
mipi_dsi_pixel_format_to_bpp(). This avoids the assert from 1. but is wrong
since the pipe is actually running at the value configured in PIPECONF.
This commit drops the override of pipe_bpp from bxt_dsi_get_pipe_config().
3) The dsi encoder's compute_config() never assigns a value to pipe_bpp,
unlike most other encoders. Falling back on compute_baseline_pipe_bpp()
which always picks 24. 24 is only correct for MIPI_DSI_FMT_RGB88 for the
others we should use 18 bpp so that we correctly do 6bpc color dithering.
This commit adds code to intel_dsi_compute_config() to properly set
pipe_bpp based on intel_dsi->pixel_format.
Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
---
drivers/gpu/drm/i915/intel_dsi.h | 4 ++--
drivers/gpu/drm/i915/vlv_dsi.c | 17 ++++++++--------
drivers/gpu/drm/i915/vlv_dsi_pll.c | 31 ++++++------------------------
3 files changed, 17 insertions(+), 35 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_dsi.h b/drivers/gpu/drm/i915/intel_dsi.h
index c888c219835f..c796a2962a43 100644
--- a/drivers/gpu/drm/i915/intel_dsi.h
+++ b/drivers/gpu/drm/i915/intel_dsi.h
@@ -160,7 +160,7 @@ int vlv_dsi_pll_compute(struct intel_encoder *encoder,
void vlv_dsi_pll_enable(struct intel_encoder *encoder,
const struct intel_crtc_state *config);
void vlv_dsi_pll_disable(struct intel_encoder *encoder);
-u32 vlv_dsi_get_pclk(struct intel_encoder *encoder, int pipe_bpp,
+u32 vlv_dsi_get_pclk(struct intel_encoder *encoder,
struct intel_crtc_state *config);
void vlv_dsi_reset_clocks(struct intel_encoder *encoder, enum port port);
@@ -170,7 +170,7 @@ int bxt_dsi_pll_compute(struct intel_encoder *encoder,
void bxt_dsi_pll_enable(struct intel_encoder *encoder,
const struct intel_crtc_state *config);
void bxt_dsi_pll_disable(struct intel_encoder *encoder);
-u32 bxt_dsi_get_pclk(struct intel_encoder *encoder, int pipe_bpp,
+u32 bxt_dsi_get_pclk(struct intel_encoder *encoder,
struct intel_crtc_state *config);
void bxt_dsi_reset_clocks(struct intel_encoder *encoder, enum port port);
diff --git a/drivers/gpu/drm/i915/vlv_dsi.c b/drivers/gpu/drm/i915/vlv_dsi.c
index be3af5f6c7a0..c10def5efa22 100644
--- a/drivers/gpu/drm/i915/vlv_dsi.c
+++ b/drivers/gpu/drm/i915/vlv_dsi.c
@@ -322,6 +322,11 @@ static bool intel_dsi_compute_config(struct intel_encoder *encoder,
/* DSI uses short packets for sync events, so clear mode flags for DSI */
adjusted_mode->flags = 0;
+ if (intel_dsi->pixel_format == MIPI_DSI_FMT_RGB888)
+ pipe_config->pipe_bpp = 24;
+ else
+ pipe_config->pipe_bpp = 18;
+
if (IS_GEN9_LP(dev_priv)) {
/* Enable Frame time stamp based scanline reporting */
adjusted_mode->private_flags |=
@@ -1097,10 +1102,8 @@ static void bxt_dsi_get_pipe_config(struct intel_encoder *encoder,
}
fmt = I915_READ(MIPI_DSI_FUNC_PRG(port)) & VID_MODE_FORMAT_MASK;
- pipe_config->pipe_bpp =
- mipi_dsi_pixel_format_to_bpp(
- pixel_format_from_register_bits(fmt));
- bpp = pipe_config->pipe_bpp;
+ bpp = mipi_dsi_pixel_format_to_bpp(
+ pixel_format_from_register_bits(fmt));
/* Enable Frame time stamo based scanline reporting */
adjusted_mode->private_flags |=
@@ -1238,11 +1241,9 @@ static void intel_dsi_get_config(struct intel_encoder *encoder,
if (IS_GEN9_LP(dev_priv)) {
bxt_dsi_get_pipe_config(encoder, pipe_config);
- pclk = bxt_dsi_get_pclk(encoder, pipe_config->pipe_bpp,
- pipe_config);
+ pclk = bxt_dsi_get_pclk(encoder, pipe_config);
} else {
- pclk = vlv_dsi_get_pclk(encoder, pipe_config->pipe_bpp,
- pipe_config);
+ pclk = vlv_dsi_get_pclk(encoder, pipe_config);
}
if (pclk) {
diff --git a/drivers/gpu/drm/i915/vlv_dsi_pll.c b/drivers/gpu/drm/i915/vlv_dsi_pll.c
index a132a8037ecc..954d5a8c4fa7 100644
--- a/drivers/gpu/drm/i915/vlv_dsi_pll.c
+++ b/drivers/gpu/drm/i915/vlv_dsi_pll.c
@@ -252,20 +252,12 @@ void bxt_dsi_pll_disable(struct intel_encoder *encoder)
DRM_ERROR("Timeout waiting for PLL lock deassertion\n");
}
-static void assert_bpp_mismatch(enum mipi_dsi_pixel_format fmt, int pipe_bpp)
-{
- int bpp = mipi_dsi_pixel_format_to_bpp(fmt);
-
- WARN(bpp != pipe_bpp,
- "bpp match assertion failure (expected %d, current %d)\n",
- bpp, pipe_bpp);
-}
-
-u32 vlv_dsi_get_pclk(struct intel_encoder *encoder, int pipe_bpp,
+u32 vlv_dsi_get_pclk(struct intel_encoder *encoder,
struct intel_crtc_state *config)
{
struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);
+ int bpp = mipi_dsi_pixel_format_to_bpp(intel_dsi->pixel_format);
u32 dsi_clock, pclk;
u32 pll_ctl, pll_div;
u32 m = 0, p = 0, n;
@@ -319,15 +311,12 @@ u32 vlv_dsi_get_pclk(struct intel_encoder *encoder, int pipe_bpp,
dsi_clock = (m * refclk) / (p * n);
- /* pixel_format and pipe_bpp should agree */
- assert_bpp_mismatch(intel_dsi->pixel_format, pipe_bpp);
-
- pclk = DIV_ROUND_CLOSEST(dsi_clock * intel_dsi->lane_count, pipe_bpp);
+ pclk = DIV_ROUND_CLOSEST(dsi_clock * intel_dsi->lane_count, bpp);
return pclk;
}
-u32 bxt_dsi_get_pclk(struct intel_encoder *encoder, int pipe_bpp,
+u32 bxt_dsi_get_pclk(struct intel_encoder *encoder,
struct intel_crtc_state *config)
{
u32 pclk;
@@ -335,12 +324,7 @@ u32 bxt_dsi_get_pclk(struct intel_encoder *encoder, int pipe_bpp,
u32 dsi_ratio;
struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);
struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
-
- /* Divide by zero */
- if (!pipe_bpp) {
- DRM_ERROR("Invalid BPP(0)\n");
- return 0;
- }
+ int bpp = mipi_dsi_pixel_format_to_bpp(intel_dsi->pixel_format);
config->dsi_pll.ctrl = I915_READ(BXT_DSI_PLL_CTL);
@@ -348,10 +332,7 @@ u32 bxt_dsi_get_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);
-
- pclk = DIV_ROUND_CLOSEST(dsi_clk * intel_dsi->lane_count, pipe_bpp);
+ pclk = DIV_ROUND_CLOSEST(dsi_clk * intel_dsi->lane_count, bpp);
DRM_DEBUG_DRIVER("Calculated pclk=%u\n", pclk);
return pclk;
--
2.19.1
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