linux-kernel - Re: [PATCH v3 0/8] NVIDIA Tegra clocksource driver improvements

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20190531082634.GA6070@pdeschrijver-desktop.Nvidia.com>
Date:   Fri, 31 May 2019 11:26:34 +0300
From:   Peter De Schrijver <pdeschrijver@...dia.com>
To:     Dmitry Osipenko <digetx@...il.com>
CC:     Daniel Lezcano <daniel.lezcano@...aro.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Joseph Lo <josephl@...dia.com>,
        Thierry Reding <thierry.reding@...il.com>,
        Jonathan Hunter <jonathanh@...dia.com>,
        <linux-tegra@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        Nicolas Chauvet <kwizart@...il.com>
Subject: Re: [PATCH v3 0/8] NVIDIA Tegra clocksource driver improvements

On Fri, May 24, 2019 at 06:32:45PM +0300, Dmitry Osipenko wrote:
> Hello,
> 
> This series primarily unifies the driver code across all Tegra SoC
> generations. In a result the clocksources are allocated per-CPU on
> older Tegra's and have a higher rating than the arch-timer, the newer
> Tegra210 is getting support for microsecond clocksource and the driver's
> code is getting much cleaner. Note that arch-timer usage is discouraged on
> all Tegra's due to the time jitter caused by the CPU frequency scaling.

I think the limitations are more as follows:

Chip	timer		suffers cpu dvfs jitter		can wakeup from cc7
T20	us-timer	No				Yes
T20	twd timer	Yes				No?
T30	us-timer	No				Yes
T30	twd timer	Yes				No?
T114	us-timer	No				Yes
T114	arch timer	No				Yes
T124	us-timer	No				Yes
T124	arch timer	No				Yes
T210	us-timer	No				Yes
T210	arch timer	No				No
T210	clk_m timer	No				Yes

right?

Peter.