From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail177-1.suw61.mandrillapp.com ([198.2.177.1]:9173 "EHLO mail177-1.suw61.mandrillapp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752869AbcCATty (ORCPT ); Tue, 1 Mar 2016 14:49:54 -0500 Received: from pmta06.mandrill.prod.suw01.rsglab.com (127.0.0.1) by mail177-1.suw61.mandrillapp.com id hqnp6422rtkl for ; Tue, 1 Mar 2016 19:49:53 +0000 (envelope-from ) From: Subject: Patch "drm: Add drm_fixp_from_fraction and drm_fixp2int_ceil" has been added to the 4.4-stable tree To: , , , , Cc: , Message-Id: <14568617915348@kroah.com> Date: Tue, 01 Mar 2016 19:49:53 +0000 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled drm: Add drm_fixp_from_fraction and drm_fixp2int_ceil to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: drm-add-drm_fixp_from_fraction-and-drm_fixp2int_ceil.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From 64566b5e767f9bc3161055ca1b443a51afb52aad Mon Sep 17 00:00:00 2001 From: Harry Wentland Date: Fri, 22 Jan 2016 17:07:25 -0500 Subject: drm: Add drm_fixp_from_fraction and drm_fixp2int_ceil From: Harry Wentland commit 64566b5e767f9bc3161055ca1b443a51afb52aad upstream. drm_fixp_from_fraction allows us to create a fixed point directly from a fraction, rather than creating fixed point values and dividing later. This avoids overflow of our 64 bit value for large numbers. drm_fixp2int_ceil allows us to return the ceiling of our fixed point value. [airlied: squash Jordan's fix] 32-bit-build-fix: Jordan Lazare Signed-off-by: Harry Wentland Reviewed-by: Alex Deucher Signed-off-by: Dave Airlie Signed-off-by: Greg Kroah-Hartman --- include/drm/drm_fixed.h | 53 ++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 51 insertions(+), 2 deletions(-) --- a/include/drm/drm_fixed.h +++ b/include/drm/drm_fixed.h @@ -73,18 +73,28 @@ static inline u32 dfixed_div(fixed20_12 #define DRM_FIXED_ONE (1ULL << DRM_FIXED_POINT) #define DRM_FIXED_DECIMAL_MASK (DRM_FIXED_ONE - 1) #define DRM_FIXED_DIGITS_MASK (~DRM_FIXED_DECIMAL_MASK) +#define DRM_FIXED_EPSILON 1LL +#define DRM_FIXED_ALMOST_ONE (DRM_FIXED_ONE - DRM_FIXED_EPSILON) static inline s64 drm_int2fixp(int a) { return ((s64)a) << DRM_FIXED_POINT; } -static inline int drm_fixp2int(int64_t a) +static inline int drm_fixp2int(s64 a) { return ((s64)a) >> DRM_FIXED_POINT; } -static inline unsigned drm_fixp_msbset(int64_t a) +static inline int drm_fixp2int_ceil(s64 a) +{ + if (a > 0) + return drm_fixp2int(a + DRM_FIXED_ALMOST_ONE); + else + return drm_fixp2int(a - DRM_FIXED_ALMOST_ONE); +} + +static inline unsigned drm_fixp_msbset(s64 a) { unsigned shift, sign = (a >> 63) & 1; @@ -136,6 +146,45 @@ static inline s64 drm_fixp_div(s64 a, s6 return result; } +static inline s64 drm_fixp_from_fraction(s64 a, s64 b) +{ + s64 res; + bool a_neg = a < 0; + bool b_neg = b < 0; + u64 a_abs = a_neg ? -a : a; + u64 b_abs = b_neg ? -b : b; + u64 rem; + + /* determine integer part */ + u64 res_abs = div64_u64_rem(a_abs, b_abs, &rem); + + /* determine fractional part */ + { + u32 i = DRM_FIXED_POINT; + + do { + rem <<= 1; + res_abs <<= 1; + if (rem >= b_abs) { + res_abs |= 1; + rem -= b_abs; + } + } while (--i != 0); + } + + /* round up LSB */ + { + u64 summand = (rem << 1) >= b_abs; + + res_abs += summand; + } + + res = (s64) res_abs; + if (a_neg ^ b_neg) + res = -res; + return res; +} + static inline s64 drm_fixp_exp(s64 x) { s64 tolerance = div64_s64(DRM_FIXED_ONE, 1000000); Patches currently in stable-queue which might be from harry.wentland@amd.com are queue-4.4/drm-add-drm_fixp_from_fraction-and-drm_fixp2int_ceil.patch queue-4.4/drm-dp-mst-move-guid-storage-from-mgr-port-to-only-mst-branch.patch queue-4.4/drm-dp-mst-calculate-mst-pbn-with-31.32-fixed-point.patch queue-4.4/drm-dp-mst-reverse-order-of-mst-enable-and-clearing-vc-payload-table.patch