6.15-stable review patch. If anyone has any objections, please let me know.
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From: Ankit Nautiyal ankit.k.nautiyal@intel.com
commit 9205999e9f13a07cb29d5a8836c25afdca186007 upstream.
DIV_ROUND_CLOSEST_ULL uses do_div(), which expects a 32-bit divisor. When passing a 64-bit constant like CURVE2_MULTIPLIER, the value is silently truncated to u32, potentially leading to incorrect results on large divisors.
Replace DIV_ROUND_CLOSEST_ULL with DIV64_U64_ROUND_CLOSEST which correctly handles full 64-bit division.
v2: Use DIV64_U64_ROUND_CLOSEST instead of div64_u64 macro. (Jani)
Fixes: 5947642004bf ("drm/i915/display: Add support for SNPS PHY HDMI PLL algorithm for DG2") Reported-by: Vas Novikov vasya.novikov@gmail.com Closes: https://lore.kernel.org/all/8d7c7958-9558-4c8a-a81a-e9310f2d8852@gmail.com/ Cc: Ankit Nautiyal ankit.k.nautiyal@intel.com Cc: Suraj Kandpal suraj.kandpal@intel.com Cc: Jani Nikula jani.nikula@intel.com Cc: Vas Novikov vasya.novikov@gmail.com Cc: stable@vger.kernel.org # v6.15+ Reviewed-by: Jani Nikula jani.nikula@intel.com Signed-off-by: Ankit Nautiyal ankit.k.nautiyal@intel.com Link: https://lore.kernel.org/r/20250618130951.1596587-2-ankit.k.nautiyal@intel.co... (cherry picked from commit b300a175a11e6a934d728317dc39787723cc7917) Signed-off-by: Joonas Lahtinen joonas.lahtinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/gpu/drm/i915/display/intel_snps_hdmi_pll.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/display/intel_snps_hdmi_pll.c b/drivers/gpu/drm/i915/display/intel_snps_hdmi_pll.c index 74bb3bedf30f..5111bdc3075b 100644 --- a/drivers/gpu/drm/i915/display/intel_snps_hdmi_pll.c +++ b/drivers/gpu/drm/i915/display/intel_snps_hdmi_pll.c @@ -103,8 +103,8 @@ static void get_ana_cp_int_prop(u64 vco_clk, DIV_ROUND_DOWN_ULL(curve_1_interpolated, CURVE0_MULTIPLIER)));
ana_cp_int_temp = - DIV_ROUND_CLOSEST_ULL(DIV_ROUND_DOWN_ULL(adjusted_vco_clk1, curve_2_scaled1), - CURVE2_MULTIPLIER); + DIV64_U64_ROUND_CLOSEST(DIV_ROUND_DOWN_ULL(adjusted_vco_clk1, curve_2_scaled1), + CURVE2_MULTIPLIER);
*ana_cp_int = max(1, min(ana_cp_int_temp, 127));