lkml.org 
[lkml]   [2019]   [May]   [31]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH v3 0/8] NVIDIA Tegra clocksource driver improvements
From
Date
On 31/05/2019 14:33, Dmitry Osipenko wrote:
> 31.05.2019 11:26, Peter De Schrijver пишет:
>> 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?
>
> Doesn't arch timer run off the CPU clock? If yes (that's what I
> assumed), then it should be affected by the DVFS. Otherwise I'll lower
> the clocksource's rating for T114/124/132.
>
> TWD can't wake CPU from the power-down state, so it's a solid "No" for
> TWD in the "can wakeup from cc7" column.

Wouldn't make sense to rename the timer-tegra20.c to timer-tegra.c now ?


--
<http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs

Follow Linaro: <http://www.facebook.com/pages/Linaro> Facebook |
<http://twitter.com/#!/linaroorg> Twitter |
<http://www.linaro.org/linaro-blog/> Blog

\
 
 \ /
  Last update: 2019-05-31 22:32    [W:0.084 / U:0.136 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site