From: Ville Syrjälä <[email protected]> Reject modes whose linetime exceeds 64 usec.
First reason being that WM_LINETIME is limited to (nearly) 64 usec. Additionally knowing the linetime is bounded will help with determining whether overflows may be a concern during various calculations. I decided to round up, and accept the linetime==64 case. We use various rounding directions for this in other parts of the code, so I feel this provides the most consistent result all around. Reviewed-by: Uma Shankar <[email protected]> Signed-off-by: Ville Syrjälä <[email protected]> --- drivers/gpu/drm/i915/display/intel_display.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c index d5b2612d4ec2..4395852e9641 100644 --- a/drivers/gpu/drm/i915/display/intel_display.c +++ b/drivers/gpu/drm/i915/display/intel_display.c @@ -7972,6 +7972,14 @@ enum drm_mode_status intel_mode_valid(struct drm_device *dev, mode->vtotal > vtotal_max) return MODE_V_ILLEGAL; + /* + * WM_LINETIME only goes up to (almost) 64 usec, and also + * knowing that the linetime is always bounded will ease the + * mind during various calculations. + */ + if (DIV_ROUND_UP(mode->htotal * 1000, mode->clock) > 64) + return MODE_H_ILLEGAL; + return MODE_OK; } -- 2.49.1
