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drm/i915/dsi: Fix pipe_bpp for handling for 6 bpc pixel-formats

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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@redhat.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181201113148.23184-1-hdegoede@redhat.com
This commit is contained in:
Hans de Goede 2018-12-01 12:31:45 +01:00
parent f1e9c90947
commit ca0b04db14
3 changed files with 17 additions and 35 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
drivers/gpu/drm/i915/intel_dsi.h
View File

@ -173,7 +173,7 @@ 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);
@ -183,7 +183,7 @@ 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);

17
drivers/gpu/drm/i915/vlv_dsi.c
View File

@ -289,6 +289,11 @@ static int 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 |=
@ -1059,10 +1064,8 @@ 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 |=
@ -1200,11 +1203,9 @@ 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) {

31
drivers/gpu/drm/i915/vlv_dsi_pll.c
View File

@ -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;