From 7176dca94314bada5b715611b2a54630ee68e48f Mon Sep 17 00:00:00 2001 From: =?utf8?q?Ville=20Syrj=C3=A4l=C3=A4?= Date: Wed, 5 Jul 2023 23:21:13 +0300 Subject: [PATCH] drm/i915: Don't warn about zero N/P in *_calc_dpll_params() MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Allow *_calc_dpll_params() to be called even if the N/P dividers are zero without warning. We'll want to call these to make sure the derived values are fully computed, but not all users (VLV DSI in particular) even enable the DPLL and thus the dividers will be left at zero. It could also be possible that the BIOS has misprogrammed the DPLL (IIRC happened with some SNB machines with 4k+ displays) and thus we'll currently generate a lot of dmesg spew. Better be silent and just let the normal state checker/etc. deal with any driver bugs. Signed-off-by: Ville Syrjälä Link: https://patchwork.freedesktop.org/patch/msgid/20230705202122.17915-5-ville.syrjala@linux.intel.com Reviewed-by: Jani Nikula --- drivers/gpu/drm/i915/display/intel_dpll.c | 37 ++++++++++++----------- 1 file changed, 20 insertions(+), 17 deletions(-) diff --git a/drivers/gpu/drm/i915/display/intel_dpll.c b/drivers/gpu/drm/i915/display/intel_dpll.c index 999badfe2906..71bfeea4cef2 100644 --- a/drivers/gpu/drm/i915/display/intel_dpll.c +++ b/drivers/gpu/drm/i915/display/intel_dpll.c @@ -314,10 +314,11 @@ int pnv_calc_dpll_params(int refclk, struct dpll *clock) { clock->m = clock->m2 + 2; clock->p = clock->p1 * clock->p2; - if (WARN_ON(clock->n == 0 || clock->p == 0)) - return 0; - clock->vco = DIV_ROUND_CLOSEST(refclk * clock->m, clock->n); - clock->dot = DIV_ROUND_CLOSEST(clock->vco, clock->p); + + clock->vco = clock->n == 0 ? 0 : + DIV_ROUND_CLOSEST(refclk * clock->m, clock->n); + clock->dot = clock->p == 0 ? 0 : + DIV_ROUND_CLOSEST(clock->vco, clock->p); return clock->dot; } @@ -331,10 +332,11 @@ int i9xx_calc_dpll_params(int refclk, struct dpll *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 0; - clock->vco = DIV_ROUND_CLOSEST(refclk * clock->m, clock->n + 2); - clock->dot = DIV_ROUND_CLOSEST(clock->vco, clock->p); + + clock->vco = clock->n + 2 == 0 ? 0 : + DIV_ROUND_CLOSEST(refclk * clock->m, clock->n + 2); + clock->dot = clock->p == 0 ? 0 : + DIV_ROUND_CLOSEST(clock->vco, clock->p); return clock->dot; } @@ -343,10 +345,11 @@ int vlv_calc_dpll_params(int refclk, struct dpll *clock) { clock->m = clock->m1 * clock->m2; clock->p = clock->p1 * clock->p2 * 5; - if (WARN_ON(clock->n == 0 || clock->p == 0)) - return 0; - clock->vco = DIV_ROUND_CLOSEST(refclk * clock->m, clock->n); - clock->dot = DIV_ROUND_CLOSEST(clock->vco, clock->p); + + clock->vco = clock->n == 0 ? 0 : + DIV_ROUND_CLOSEST(refclk * clock->m, clock->n); + clock->dot = clock->p == 0 ? 0 : + DIV_ROUND_CLOSEST(clock->vco, clock->p); return clock->dot; } @@ -355,11 +358,11 @@ int chv_calc_dpll_params(int refclk, struct dpll *clock) { clock->m = clock->m1 * clock->m2; clock->p = clock->p1 * clock->p2 * 5; - if (WARN_ON(clock->n == 0 || clock->p == 0)) - return 0; - clock->vco = DIV_ROUND_CLOSEST_ULL(mul_u32_u32(refclk, clock->m), - clock->n << 22); - clock->dot = DIV_ROUND_CLOSEST(clock->vco, clock->p); + + clock->vco = clock->n == 0 ? 0 : + DIV_ROUND_CLOSEST_ULL(mul_u32_u32(refclk, clock->m), clock->n << 22); + clock->dot = clock->p == 0 ? 0 : + DIV_ROUND_CLOSEST(clock->vco, clock->p); return clock->dot; } -- 2.20.1