linux-kernel - rtc regression [463a86304cae ("char/genrtc: x86: remove remnants of asm/rtc.h")]

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Message-ID: <20160809155649.GX4329@intel.com>
Date:	Tue, 9 Aug 2016 18:56:49 +0300
From:	Ville Syrjälä <ville.syrjala@...ux.intel.com>
To:	Arnd Bergmann <arnd@...db.de>
Cc:	Geert Uytterhoeven <geert@...ux-m68k.org>,
	Alexandre Belloni <alexandre.belloni@...e-electrons.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	"H. Peter Anvin" <hpa@...or.com>, x86@...nel.org,
	Alessandro Zummo <a.zummo@...ertech.it>,
	linux-kernel@...r.kernel.org, rtc-linux@...glegroups.com
Subject: rtc regression [463a86304cae ("char/genrtc: x86: remove remnants of
 asm/rtc.h")]

Hi,

commit 463a86304cae ("char/genrtc: x86: remove remnants of asm/rtc.h")
broke rtc for me. Neither hwclock or rtcwake work anymore. This is just
a very standard x86-64 IVB box, and it was reported that machines in
our i915 test farm are having rtc related problems as well.

The first time I run hwclock after rebooting I get this:
 open("/dev/rtc", O_RDONLY)              = 3
 ioctl(3, PHN_SET_REGS or RTC_UIE_ON, 0) = 0
 select(4, [3], NULL, NULL, {10, 0})     = 0 (Timeout)
 ioctl(3, PHN_NOT_OH or RTC_UIE_OFF, 0)  = 0
 close(3)                                = 0

On all subsequent runs I get this:
 open("/dev/rtc", O_RDONLY)              = 3
 ioctl(3, PHN_SET_REGS or RTC_UIE_ON, 0) = -1 EINVAL (Invalid argument)
 ioctl(3, RTC_RD_TIME, 0x7ffd76b3ae70)   = -1 EINVAL (Invalid argument)
 close(3)                                = 0

463a86304cae^ gets me back to working condition:
 open("/dev/rtc", O_RDONLY)              = 3
 ioctl(3, PHN_SET_REGS or RTC_UIE_ON, 0) = 0
 select(4, [3], NULL, NULL, {10, 0})     = 1 (in [3], left {9, 530998})
 ioctl(3, PHN_NOT_OH or RTC_UIE_OFF, 0)  = 0
 ioctl(3, RTC_RD_TIME, {tm_sec=20, tm_min=17, tm_hour=15, tm_mday=9, tm_mon=7, tm_year=116, ...}) = 0
 close(3)                                = 0

-- 
Ville Syrjälä
Intel OTC