From: Fu Wei <fu.wei@linaro.org>
To: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>,
Len Brown <lenb@kernel.org>,
Daniel Lezcano <daniel.lezcano@linaro.org>,
Thomas Gleixner <tglx@linutronix.de>,
Marc Zyngier <marc.zyngier@arm.com>,
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<linux-arm-kernel@lists.infradead.org>,
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Christoffer Dall <christoffer.dall@linaro.org>,
Julien Grall <julien.grall@arm.com>
Subject: Re: [PATCH v7 4/9] acpi/arm64: Add GTDT table parse driver
Date: Wed, 20 Jul 2016 02:25:35 +0800 [thread overview]
Message-ID: <CADyBb7uiu2d-6bkA6qg9rWCePrZPtv3aMktXUvn7UciiR-WLhA@mail.gmail.com> (raw)
In-Reply-To: <16716612.zdLA2RMyjn@vostro.rjw.lan>
Hi Rafael,
On 16 July 2016 at 20:35, Rafael J. Wysocki <rjw@rjwysocki.net> wrote:
> On Saturday, July 16, 2016 10:24:35 AM Fu Wei wrote:
>> Hi Rafeal,
>>
>> On 16 July 2016 at 05:22, Rafael J. Wysocki <rjw@rjwysocki.net> wrote:
>> > On Saturday, July 16, 2016 12:32:14 AM Fu Wei wrote:
>> >> Hi Rafael,
>> >>
>> >> On 15 July 2016 at 21:07, Rafael J. Wysocki <rjw@rjwysocki.net> wrote:
>> >> > On Friday, July 15, 2016 02:15:27 PM Rafael J. Wysocki wrote:
>> >> >> On Friday, July 15, 2016 03:32:35 PM Fu Wei wrote:
>> >> >> > Hi Rafael,
>> >> >> >
>> >> >
>> >> > [cut]
>> >> >
>> >> >> > >
>> >> >> > >> + return 0;
>> >> >> > >> + }
>> >> >> > >> +
>> >> >> > >> + if (!gtdt->platform_timer_count) {
>> >> >> > >> + pr_info("No Platform Timer.\n");
>> >> >> > >> + return 0;
>> >> >> > >> + }
>> >> >> > >> +
>> >> >> > >> + acpi_gtdt_desc.platform_timer_start = (void *)gtdt +
>> >> >> > >> + gtdt->platform_timer_offset;
>> >> >> > >> + if (acpi_gtdt_desc.platform_timer_start <
>> >> >> > >> + (void *)table + sizeof(struct acpi_table_gtdt)) {
>> >> >> > >> + pr_err(FW_BUG "Platform Timer pointer error.\n");
>> >> >> > >
>> >> >> > > Why pr_err()?
>> >> >> >
>> >> >> > if (true), that means the GTDT table has bugs.
>> >> >> >
>> >> >>
>> >> >> And that's not a very useful piece of information unless you're debugging the
>> >> >> platform, is it?
>> >> >
>> >> > FWIW, I'm not a big fan of printing "your firmware is buggy" type of messages
>> >> > (especially at the "error" log level or higher) unless they can be clearly
>> >> > connected to a specific type of functional failure.
>> >> >
>> >> > So if you want to pring an error-level message, something like "I cannot do X
>> >> > because of the firmware bug Y" would be better IMO.
>> >>
>> >> So can I do this:
>> >> pr_err(FW_BUG "Can NOT init platform_timer pointer, because of the
>> >> GTDT table bug\n");
>> >>
>> >> or pr_debug(FW_BUG "Can NOT init platform_timer_start, because of
>> >> platform_timer_offset bug in GTDT\n");
>> >>
>> >> or just delete it?
>> >>
>> >> which one do you prefer? I think maybe should provide some clue for
>> >> users to fix the problem :-)
>> >
>> > And how exactly would they fix it then?
>> >
>> >>
>> >> any thought ?
>> >
>> > If you print variable or function names and the like, the message should be
>> > a debug one, because that's information that can only be understood by
>> > developers (some developers are users too, but they are a minority).
>> >
>> > If you want to report an error, say what is not working (or not available
>> > etc) and why (if you know the reason at the time the message is printed).
>>
>> Great thanks, I guess I got you point.
>>
>> maybe just a very simple message like:
>> pr_err(FW_BUG "Failed to init table: GTDT table is buggy.\n");
>
> To understand this message one needs to know what "table" means here
> and what "GTDT" is. Also the prefix already will be something like
> "ACPI: GTDT:", so repeating part of it is not really useful IMO.
>
> Can you tell me please what's not going to work when that message is printed?
>
> Will the system boot at all then? If so, the functionality will be limited
> somehow I suppose. How is it going to be limited?
when that message is printed, all kind of platform timer(memory-mapped
timer and SBSA watchdog) can't work.
actually, I think system can boot without them.
I have updated this on my v8(just posted), let's discuss this on v8 :-)
>
>> I will also check other pr_* , if I can update them
>
> OK, great!
>
> Thanks,
> Rafael
>
--
Best regards,
Fu Wei
Software Engineer
Red Hat
next prev parent reply other threads:[~2016-07-19 18:25 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-13 17:53 [PATCH v7 0/9] acpi, clocksource: add GTDT driver and GTDT support in arm_arch_timer fu.wei
2016-07-13 17:53 ` [PATCH v7 1/9] clocksource/drivers/arm_arch_timer: Move enums and defines to header file fu.wei
2016-07-13 17:53 ` [PATCH v7 2/9] clocksource/drivers/arm_arch_timer: Add a new enum for spi type fu.wei
2016-07-13 17:53 ` [PATCH v7 3/9] clocksource/drivers/arm_arch_timer: Improve printk relevant code fu.wei
2016-07-13 17:53 ` [PATCH v7 4/9] acpi/arm64: Add GTDT table parse driver fu.wei
2016-07-13 20:30 ` Rafael J. Wysocki
2016-07-13 20:39 ` Rafael J. Wysocki
2016-07-15 7:33 ` Fu Wei
2016-07-13 21:08 ` Guenter Roeck
2016-07-13 21:43 ` Rafael J. Wysocki
2016-07-15 7:45 ` Fu Wei
2016-07-15 12:11 ` Rafael J. Wysocki
2016-07-15 16:13 ` Fu Wei
2016-07-15 7:32 ` Fu Wei
2016-07-15 12:15 ` Rafael J. Wysocki
2016-07-15 13:07 ` Rafael J. Wysocki
2016-07-15 16:32 ` Fu Wei
2016-07-15 21:22 ` Rafael J. Wysocki
2016-07-16 2:24 ` Fu Wei
2016-07-16 12:35 ` Rafael J. Wysocki
2016-07-19 18:25 ` Fu Wei [this message]
2016-07-14 20:33 ` Paul Gortmaker
2016-07-15 7:46 ` Fu Wei
2016-07-13 17:53 ` [PATCH v7 5/9] MAINTAINERS / ACPI: add the ARM64-specific ACPI Support maintainers fu.wei
2016-07-13 20:16 ` Rafael J. Wysocki
2016-07-15 1:02 ` Fu Wei
2016-07-13 17:53 ` [PATCH v7 6/9] clocksource/drivers/arm_arch_timer: Simplify ACPI support code fu.wei
2016-07-13 17:53 ` [PATCH v7 7/9] acpi/arm64: Add memory-mapped timer support in GTDT driver fu.wei
2016-07-14 13:42 ` Lorenzo Pieralisi
2016-07-19 18:28 ` Fu Wei
2016-07-13 17:53 ` [PATCH v7 8/9] clocksource/drivers/arm_arch_timer: Add GTDT support for memory-mapped timer fu.wei
2016-07-13 17:53 ` [PATCH v7 9/9] acpi/arm64: Add SBSA Generic Watchdog support in GTDT driver fu.wei
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