From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-io0-f174.google.com ([209.85.223.174]:33183 "EHLO mail-io0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965175AbbHKPXB (ORCPT ); Tue, 11 Aug 2015 11:23:01 -0400 Received: by iods203 with SMTP id s203so8662926iod.0 for ; Tue, 11 Aug 2015 08:23:01 -0700 (PDT) From: Abhilash Jindal To: linux-media@vger.kernel.org Cc: mchehab@osg.samsung.com, Abhilash Jindal Subject: [PATCH] [media] bt8xxx: Use monotonic time Date: Tue, 11 Aug 2015 11:22:57 -0400 Message-Id: <1439306577-3281-1-git-send-email-klock.android@gmail.com> Sender: linux-media-owner@vger.kernel.org List-ID: Wall time obtained from do_gettimeofday is susceptible to sudden jumps due to user setting the time or due to NTP. Monotonic time is constantly increasing time better suited for comparing two timestamps. Signed-off-by: Abhilash Jindal --- drivers/media/pci/bt8xx/bttv-input.c | 23 +++++++++-------------- drivers/media/pci/bt8xx/bttvp.h | 2 +- 2 files changed, 10 insertions(+), 15 deletions(-) diff --git a/drivers/media/pci/bt8xx/bttv-input.c b/drivers/media/pci/bt8xx/bttv-input.c index 67c8d6b..0f21771 100644 --- a/drivers/media/pci/bt8xx/bttv-input.c +++ b/drivers/media/pci/bt8xx/bttv-input.c @@ -194,21 +194,18 @@ static u32 bttv_rc5_decode(unsigned int code) static void bttv_rc5_timer_end(unsigned long data) { struct bttv_ir *ir = (struct bttv_ir *)data; - struct timeval tv; + ktime_t tv; u32 gap, rc5, scancode; u8 toggle, command, system; /* get time */ - do_gettimeofday(&tv); + tv = ktime_get(); + gap = ktime_to_us(ktime_sub(tv, ir->base_time)); /* avoid overflow with gap >1s */ - if (tv.tv_sec - ir->base_time.tv_sec > 1) { + if (gap > USEC_PER_SEC) { gap = 200000; - } else { - gap = 1000000 * (tv.tv_sec - ir->base_time.tv_sec) + - tv.tv_usec - ir->base_time.tv_usec; - } - + } /* signal we're ready to start a new code */ ir->active = false; @@ -249,7 +246,7 @@ static void bttv_rc5_timer_end(unsigned long data) static int bttv_rc5_irq(struct bttv *btv) { struct bttv_ir *ir = btv->remote; - struct timeval tv; + ktime_t tv; u32 gpio; u32 gap; unsigned long current_jiffies; @@ -259,14 +256,12 @@ static int bttv_rc5_irq(struct bttv *btv) /* get time of bit */ current_jiffies = jiffies; - do_gettimeofday(&tv); + tv = ktime_get(); + gap = ktime_to_us(ktime_sub(tv, ir->base_time)); /* avoid overflow with gap >1s */ - if (tv.tv_sec - ir->base_time.tv_sec > 1) { + if (gap > USEC_PER_SEC) { gap = 200000; - } else { - gap = 1000000 * (tv.tv_sec - ir->base_time.tv_sec) + - tv.tv_usec - ir->base_time.tv_usec; } dprintk("RC5 IRQ: gap %d us for %s\n", diff --git a/drivers/media/pci/bt8xx/bttvp.h b/drivers/media/pci/bt8xx/bttvp.h index a444cfb..31bf79d 100644 --- a/drivers/media/pci/bt8xx/bttvp.h +++ b/drivers/media/pci/bt8xx/bttvp.h @@ -140,7 +140,7 @@ struct bttv_ir { bool rc5_gpio; /* Is RC5 legacy GPIO enabled? */ u32 last_bit; /* last raw bit seen */ u32 code; /* raw code under construction */ - struct timeval base_time; /* time of last seen code */ + ktime_t base_time; /* time of last seen code */ bool active; /* building raw code */ }; -- 1.7.9.5