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Commit ed5ca77e authored by Ville Syrjälä's avatar Ville Syrjälä Committed by Daniel Vetter
Browse files

drm/i915: Avoid div-by-zero in clock calculation funcs 



Check that the N and P dividers don't cause a divide by zero.

This shouldn't happen under normal circumstances, but can
happen eg. under simulation.

Signed-off-by: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: default avatarJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
parent 7e11f9f4

drivers/gpu/drm/i915/intel_display.c

+6 −0
Original line number Diff line number Diff line
@@ -329,6 +329,8 @@ static void vlv_clock(int refclk, intel_clock_t *clock) 
{

	clock->m = clock->m1 * clock->m2;

	clock->p = clock->p1 * clock->p2;

	if (WARN_ON(clock->n == 0 || clock->p == 0))

		return;

	clock->vco = DIV_ROUND_CLOSEST(refclk * clock->m, clock->n);

	clock->dot = DIV_ROUND_CLOSEST(clock->vco, clock->p);

}
@@ -430,6 +432,8 @@ static void pineview_clock(int refclk, intel_clock_t *clock) 
{

	clock->m = clock->m2 + 2;

	clock->p = clock->p1 * clock->p2;

	if (WARN_ON(clock->n == 0 || clock->p == 0))

		return;

	clock->vco = DIV_ROUND_CLOSEST(refclk * clock->m, clock->n);

	clock->dot = DIV_ROUND_CLOSEST(clock->vco, clock->p);

}
@@ -443,6 +447,8 @@ static void i9xx_clock(int refclk, intel_clock_t *clock) 
{

	clock->m = i9xx_dpll_compute_m(clock);

	clock->p = clock->p1 * clock->p2;

	if (WARN_ON(clock->n + 2 == 0 || clock->p == 0))

		return;

	clock->vco = DIV_ROUND_CLOSEST(refclk * clock->m, clock->n + 2);

	clock->dot = DIV_ROUND_CLOSEST(clock->vco, clock->p);

}