Re: [PATCH 1/2] PM: base: power: don't try to use non-existing RTC for storing data

From: Juergen Gross <jgross@suse.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: xen-devel@lists.xenproject.org, linux-pm@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	"Rafael J. Wysocki" <rjw@rjwysocki.net>,
	Len Brown <len.brown@intel.com>, Pavel Machek <pavel@ucw.cz>,
	"Rafael J. Wysocki" <rafael@kernel.org>,
	stable@vger.kernel.org
Subject: Re: [PATCH 1/2] PM: base: power: don't try to use non-existing RTC for storing data
Date: Fri, 3 Sep 2021 11:01:58 +0200	[thread overview]
Message-ID: <1b6a8f9c-2a5f-e97e-c89d-5983ceeb20e5@suse.com> (raw)
In-Reply-To: <YTHjPbklWVDVaBfK@kroah.com>

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On 03.09.21 10:56, Greg Kroah-Hartman wrote:
> On Fri, Sep 03, 2021 at 10:49:36AM +0200, Juergen Gross wrote:
>> In there is no legacy RTC device, don't try to use it for storing trace
>> data across suspend/resume.
>>
>> Cc: <stable@vger.kernel.org>
>> Signed-off-by: Juergen Gross <jgross@suse.com>
>> ---
>>   drivers/base/power/trace.c | 10 ++++++++++
>>   1 file changed, 10 insertions(+)
>>
>> diff --git a/drivers/base/power/trace.c b/drivers/base/power/trace.c
>> index a97f33d0c59f..b7c80849455c 100644
>> --- a/drivers/base/power/trace.c
>> +++ b/drivers/base/power/trace.c
>> @@ -13,6 +13,7 @@
>>   #include <linux/export.h>
>>   #include <linux/rtc.h>
>>   #include <linux/suspend.h>
>> +#include <linux/init.h>
>>   
>>   #include <linux/mc146818rtc.h>
>>   
>> @@ -165,6 +166,9 @@ void generate_pm_trace(const void *tracedata, unsigned int user)
>>   	const char *file = *(const char **)(tracedata + 2);
>>   	unsigned int user_hash_value, file_hash_value;
>>   
>> +	if (!x86_platform.legacy.rtc)
>> +		return 0;
> 
> Why does the driver core code here care about a platform/arch-specific
> thing at all?  Did you just break all other arches?

This file is only compiled for x86. It depends on CONFIG_PM_TRACE_RTC,
which has a "depends on X86" attribute.

Juergen

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