From cdf6428dd518435a05739abf7659589de30970f4 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Ville=20Syrj=C3=A4l=C3=A4?= Date: Tue, 27 Sep 2022 21:24:55 +0300 Subject: [PATCH] drm/i915: Reject excessive dotclocks early MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Make sure modes with crazy big dotclocks are rejected early, so as to not cause problems for subsequent code via integer overflows and whatnot. These would eventually be rejected in intel_crtc_compute_pipe_mode() but that is now too late as we do the clock computations a bit earlier than that. And we don't want to just reorder the two since we still want to check the final computed dotclock against the hardware limit to make sure we didn't end up above the limit due to rounding/etc. Fixes: 0ff0e219d9b8 ("drm/i915: Compute clocks earlier") Signed-off-by: Ville Syrjälä Link: https://patchwork.freedesktop.org/patch/msgid/20220927182455.3422-1-ville.syrjala@linux.intel.com Reviewed-by: Jani Nikula (cherry picked from commit df2f59c5857b56a5cc40b6562b032c5d8d50cdfc) Signed-off-by: Tvrtko Ursulin --- drivers/gpu/drm/i915/display/intel_display.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c index accf531..f0063e0 100644 --- a/drivers/gpu/drm/i915/display/intel_display.c +++ b/drivers/gpu/drm/i915/display/intel_display.c @@ -8130,6 +8130,17 @@ static void intel_setup_outputs(struct drm_i915_private *dev_priv) drm_helper_move_panel_connectors_to_head(&dev_priv->drm); } +static int max_dotclock(struct drm_i915_private *i915) +{ + int max_dotclock = i915->max_dotclk_freq; + + /* icl+ might use bigjoiner */ + if (DISPLAY_VER(i915) >= 11) + max_dotclock *= 2; + + return max_dotclock; +} + static enum drm_mode_status intel_mode_valid(struct drm_device *dev, const struct drm_display_mode *mode) @@ -8167,6 +8178,13 @@ intel_mode_valid(struct drm_device *dev, DRM_MODE_FLAG_CLKDIV2)) return MODE_BAD; + /* + * Reject clearly excessive dotclocks early to + * avoid having to worry about huge integers later. + */ + if (mode->clock > max_dotclock(dev_priv)) + return MODE_CLOCK_HIGH; + /* Transcoder timing limits */ if (DISPLAY_VER(dev_priv) >= 11) { hdisplay_max = 16384; -- 2.7.4