Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
drm/i915: Reject modes with linetime > 64 usec
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 <uma.shankar@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20251014191808.12326-3-ville.syrjala@linux.intel.com
+8
+8
drivers/gpu/drm/i915/display/intel_display.c
+8
drivers/gpu/drm/i915/display/intel_display.c
···
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mode->vtotal > vtotal_max)
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return MODE_V_ILLEGAL;
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+
/*
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+
* WM_LINETIME only goes up to (almost) 64 usec, and also
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+
* knowing that the linetime is always bounded will ease the
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+
* mind during various calculations.
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+
*/
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+
if (DIV_ROUND_UP(mode->htotal * 1000, mode->clock) > 64)
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return MODE_H_ILLEGAL;
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+
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return MODE_OK;
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}
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