Raspberry Pi 5 在 shutdown 狀態時的電力消耗過高問題

在「Reducing Raspberry Pi 5's power consumption by 140x」這邊看到的,講 Raspberry Pi 5 在 shutdown 狀態下電力消耗過高的問題。

依據 Jeff Geerling 提到,在 shutdown 狀態下仍然會消耗 1.2W~1.6W:

Because of this, a Pi 5 will still sit there consuming 1.2-1.6W when completely shut down, even without anything plugged in except power.

也有提到解決方法是把 POWER_OFF_ON_HALT 改成 1,他給的範例另外有多一些設定,但跟這次的功耗問題無關:


依照文章裡面的說明設定好,重開再 shutdown 測試就可以看到整個降下來了:

Save that configuration and reboot, then next time you shut down, you should see power consumption go down from 1-2W to 0.01W or even less:

應該算是某種 bug 或是 regression,後續預設值應該會修正?

Raspberry Pi 5 拿掉硬體的 H.264 encoding

HN 上看到「Raspberry Pi 5 has no hardware video encoding and only HEVC decoding (raspberrypi.com)」,原文指到 Gordon Hollingworth 的回覆這邊,可以看到這是上個月的消息了。

Raspberry Pi 一直都有硬體 H.264 encoding 的能力,不過這個在 Raspberry Pi 5 上被拿掉了,所以得用軟體壓。

官方有提到 Raspberry Pi 5 的 CPU 因為比之前快很多,單顆就有辦法做到 1080p60 (而 RPi5 有 4 CPU),所以除了 power consumption 以外應該不是大問題:

Obviously, the bad thing is the power consumption, but actually it only takes around 1 processor to encode 1080p60 with our default settings (which is still better quality than the PI 4 hardware encoder).

不過 HN 上猜是授權費用之類的問題,我在想是不是新的晶片組的 encoding license 都綁在一起,H.264 + H.265 得一包一起買,而 H.265 的授權費是眾所皆知的貴...

當 desktop 應該是還好,但就心裡有個底...

Raspberry Pi 5 的一些細節出現了...

上一篇「Raspberry Pi 5」提到了一些來自 Raspberry Pi 官方的說明,後續各個媒體 (像是 YouTuber) 也都解禁放出不少資料可以參考了,其中電源的部分在「Answering some questions about the Raspberry Pi 5」這邊看到不認 USB PD 的 5V/5A 的問題,目前看起來是走獨規:

I also tested the Radxa USB-C PD 30W power adapter, which says it will output 5V at 5A, but the Pi only negotiates 3A with it right now. I've been in contact with Pi engineers and it seems like they have one on the way to test to see why it's not negotiating more.

另外看起來之後有機會支援 12V/2.25A (換算起來是 27W) 的充電頭,有機會透過韌體更新認得 PD?

I should also note the official adapter lists 12V at 2.25A output as an option, so maybe some future Pi could take that and run with it, for increased compatibility with more USB-C PD adapters (5V at 5A is a rarely seen, though it's an option in the spec).

不過即使走 5V/3A (15W),在一般的應用下是夠用了,到時候拿到來玩看看...