From: Hans de Goede hdegoede@redhat.com
Prior to this commit we fail to init the DSI panel on the GPD MicroPC: https://www.indiegogo.com/projects/gpd-micropc-6-inch-handheld-industry-lapt...
The problem is intel_dsi_vbt_init() failing with the following error: *ERROR* Burst mode freq is less than computed
The pclk in the VBT panel modeline is 70000, together with 24 bpp and 4 lines this results in a bitrate value of 70000 * 24 / 4 = 420000. But the target_burst_mode_freq in the VBT is 418000.
This commit works around this problem by adding an intel_fuzzy_clock_check when target_burst_mode_freq < bitrate and setting target_burst_mode_freq to bitrate when that checks succeeds, fixing the panel not working.
Cc: stable@vger.kernel.org Reviewed-by: Ville Syrjälä ville.syrjala@linux.intel.com Signed-off-by: Hans de Goede hdegoede@redhat.com Link: https://patchwork.freedesktop.org/patch/msgid/20190524174028.21659-2-hdegoed... (cherry picked from commit 2c1c55252647abd989b94f725b190c700312d053) Signed-off-by: Jani Nikula jani.nikula@intel.com --- drivers/gpu/drm/i915/intel_display.c | 2 +- drivers/gpu/drm/i915/intel_drv.h | 1 + drivers/gpu/drm/i915/intel_dsi_vbt.c | 11 +++++++++++ 3 files changed, 13 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index 5098228f1302..ceb78f44f087 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -11942,7 +11942,7 @@ intel_modeset_pipe_config(struct drm_crtc *crtc, return 0; }
-static bool intel_fuzzy_clock_check(int clock1, int clock2) +bool intel_fuzzy_clock_check(int clock1, int clock2) { int diff;
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h index a38b9cff5cd0..e85cd377a652 100644 --- a/drivers/gpu/drm/i915/intel_drv.h +++ b/drivers/gpu/drm/i915/intel_drv.h @@ -1742,6 +1742,7 @@ int vlv_force_pll_on(struct drm_i915_private *dev_priv, enum pipe pipe, const struct dpll *dpll); void vlv_force_pll_off(struct drm_i915_private *dev_priv, enum pipe pipe); int lpt_get_iclkip(struct drm_i915_private *dev_priv); +bool intel_fuzzy_clock_check(int clock1, int clock2);
/* modesetting asserts */ void assert_panel_unlocked(struct drm_i915_private *dev_priv, diff --git a/drivers/gpu/drm/i915/intel_dsi_vbt.c b/drivers/gpu/drm/i915/intel_dsi_vbt.c index 3074448446bc..4b8e48db1843 100644 --- a/drivers/gpu/drm/i915/intel_dsi_vbt.c +++ b/drivers/gpu/drm/i915/intel_dsi_vbt.c @@ -853,6 +853,17 @@ bool intel_dsi_vbt_init(struct intel_dsi *intel_dsi, u16 panel_id) if (mipi_config->target_burst_mode_freq) { u32 bitrate = intel_dsi_bitrate(intel_dsi);
+ /* + * Sometimes the VBT contains a slightly lower clock, + * then the bitrate we have calculated, in this case + * just replace it with the calculated bitrate. + */ + if (mipi_config->target_burst_mode_freq < bitrate && + intel_fuzzy_clock_check( + mipi_config->target_burst_mode_freq, + bitrate)) + mipi_config->target_burst_mode_freq = bitrate; + if (mipi_config->target_burst_mode_freq < bitrate) { DRM_ERROR("Burst mode freq is less than computed\n"); return false;