From: Ville Syrjälä Date: Thu, 26 Mar 2026 11:18:10 +0000 (+0200) Subject: drm/i915/dsi: Don't do DSC horizontal timing adjustments in command mode X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0b475e91ecc2313207196c6d7fd5c53e1a878525;p=thirdparty%2Flinux.git drm/i915/dsi: Don't do DSC horizontal timing adjustments in command mode Stop adjusting the horizontal timing values based on the compression ratio in command mode. Bspec seems to be telling us to do this only in video mode, and this is also how the Windows driver does things. This should also fix a div-by-zero on some machines because the adjusted htotal ends up being so small that we end up with line_time_us==0 when trying to determine the vtotal value in command mode. Note that this doesn't actually make the display on the Huawei Matebook E work, but at least the kernel no longer explodes when the driver loads. Cc: stable@vger.kernel.org Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/12045 Signed-off-by: Ville Syrjälä Link: https://patch.msgid.link/20260326111814.9800-2-ville.syrjala@linux.intel.com Fixes: 53693f02d80e ("drm/i915/dsi: account for DSC in horizontal timings") Reviewed-by: Jani Nikula --- diff --git a/drivers/gpu/drm/i915/display/icl_dsi.c b/drivers/gpu/drm/i915/display/icl_dsi.c index c043279796781..a763f2b13ff2d 100644 --- a/drivers/gpu/drm/i915/display/icl_dsi.c +++ b/drivers/gpu/drm/i915/display/icl_dsi.c @@ -888,7 +888,7 @@ gen11_dsi_set_transcoder_timings(struct intel_encoder *encoder, * non-compressed link speeds, and simplifies down to the ratio between * compressed and non-compressed bpp. */ - if (crtc_state->dsc.compression_enable) { + if (is_vid_mode(intel_dsi) && crtc_state->dsc.compression_enable) { mul = fxp_q4_to_int(crtc_state->dsc.compressed_bpp_x16); div = mipi_dsi_pixel_format_to_bpp(intel_dsi->pixel_format); } @@ -1502,7 +1502,7 @@ static void gen11_dsi_get_timings(struct intel_encoder *encoder, struct drm_display_mode *adjusted_mode = &pipe_config->hw.adjusted_mode; - if (pipe_config->dsc.compressed_bpp_x16) { + if (is_vid_mode(intel_dsi) && pipe_config->dsc.compressed_bpp_x16) { int div = fxp_q4_to_int(pipe_config->dsc.compressed_bpp_x16); int mul = mipi_dsi_pixel_format_to_bpp(intel_dsi->pixel_format);