linux-kernel - Re: [PATCH] clockevents/drivers/i8253: Do not zero timer counter in shutdown

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Message-ID: <87plqr19oj.ffs@tglx>
Date: Fri, 02 Aug 2024 12:49:32 +0200
From: Thomas Gleixner <tglx@...utronix.de>
To: David Woodhouse <dwmw2@...radead.org>, lirongqing@...du.com,
 seanjc@...gle.com, kys@...rosoft.com, haiyangz@...rosoft.com,
 wei.liu@...nel.org, decui@...rosoft.com, mingo@...hat.com, bp@...en8.de,
 dave.hansen@...ux.intel.com, x86@...nel.org, linux-hyperv@...r.kernel.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH] clockevents/drivers/i8253: Do not zero timer counter in
 shutdown

On Fri, Aug 02 2024 at 09:07, David Woodhouse wrote:
> On Thu, 2024-08-01 at 20:57 +0200, Thomas Gleixner wrote:
>> It's not counting right out of reset. But once it started counting it's
>> tedious to stop :)
>
> My reading of the data sheet definitely suggests that it *shouldn't*
> be.
>
> Mode 0 says: "The output will be initially low after the mode set
> operation. After the count is loaded into the selected count
> register... the counter will count."

Hmm. Indeed. That does not stop the counter, but it prevents the
interrupt from firing over and over.

So fine, we can go with the patch from Li, but the changelog needs a
rewrite and the code want's a big fat comment.

Thanks,

        tglx