修正 Mac 外接螢幕的 Underscan 問題

公司的 MacBook Pro (13-inch, 2017, Two Thunderbolt 3 ports) 透過 HDMI 接 Dell P2419H 一直都有 Underscan 的問題:

出自「About overscan and underscan on your Mac, Apple TV, or other display

本來想透過 Underscan slide 修改 (像是下面這張圖),但發現系統內沒有 Underscan slide。

出自「About overscan and underscan on your Mac, Apple TV, or other display

找了不少文章後後來是在「Fixing Issues with Overscan/Underscan(Black Borders) on macOS」這篇的 comment 看到解法:

Ran into this same underscan problem with black borders showing up on my new Dell 24-inch Ultrasharp U2415 connected to a 2013 Macbook Air running High Sierra, and after hours of looking into the problem the fix turned out to be super simple:

Just restart in Safe Mode.

That’s it. Restart your Mac in Safe Mode (restart, hold down the Shift key after the Apple BONG sounds, then restart normally once again for good measure. I don’t know what this clears or resets but it worked for me. No more letterboxing or black borders with the native 1920×1200 resolution selected.

So maybe something to try first for anyone coming across this post.

照著重開進 Safe mode 後再開回一般模式就正常了 (what???),先記錄起來,讓我之後遇到時可以搜尋到自己的文章...

Ubuntu 16.04 上多螢幕時登入畫面的設定問題

我的 Ubuntu 桌機在登入後的螢幕設定是這樣,設定在 ~/.config/monitors.xml 裡:

但登入時還是預設值 (四個螢幕都是打橫的),雖然只是輸入個密碼沒有什麼大礙,但還是想找個方法讓登入畫面吃到正確的 monitors.xml

查了文件在「Fixing Ubuntu’s Login Resolution」這邊發現 Ubuntu 16.04 (Unity) 是用 LightDM,在登入畫面是透過 lightdm 權限在跑,所以去 ~lightdm/.config/monitors.xml 下設定就可以了,如果用 symbolic link 的話要注意權限的問題。

不小心搞爛的話,可以用 Ctrl-Alt-F1 切到 command line 下登入修正...

Ubuntu 下雙螢幕進入省電模式後再起不能的問題

Update:後來還是有狀況,這篇的方法沒有完全解決... 等找出解法後再回來更新。

前陣子把家裡的 Ubuntu 桌機多塞了一顆 Dell 的 P2317H,打直拿來看程式碼,大致上是沒什麼問題,不過螢幕進入省電模式後就再起不能... (NVIDIA 的顯卡,一顆接 DisplayPort,另外一顆接 HDMI)

後來找到這一串討論:「DP1.2 connected monitor cannot be turned on again with DPMS」。

這串討論裡官方的人有給不少方式,後來試到第二頁的發法,是在 /etc/modprobe.d/disable-nouveau.conf 裡設定一些參數,重開機後就解決了:

blacklist nouveau
options nouveau modeset=0

看起來是 nouveau 的關係,現在總算是可以比較正常的使用了... (還有不少眉眉角角的地方要再找方法解...)


歐盟法院 (The Court of Justice of the European Union) 認為公開無線網路的營運者不需要對使用者的侵權行為負責:「EU Court: Open WiFi Operator Not Liable For Pirate Users」。

不過這是有一些前提的,法院認為應該要符合這幾個要件,營運方才不要負責。基本上完全沒有 filter 限制的無線網路會符合這些條件:

The Court further notes that in order for such ‘mere conduit’ services to be exempt from third party liability, three cumulative conditions must be met:

– The provider must not have initiated the transmission
– It must not have selected the recipient of the transmission
– It must neither have selected nor modified the information contained in the transmission.


In an effort to strike a balance between protecting a service provider from third party liability and the rights of IP owners, the Court ruled that providers can be required to end infringement.

“[T]he directive does not preclude the copyright holder from seeking before a national authority or court to have such a service provider ordered to end, or prevent, any infringement of copyright committed by its customers,” the Court found.

One such measure could include the obtaining of an injunction which would force an operator to password-protect his open WiFi network in order to deter infringement.


On a more positive note, the Court rejected the notion of monitoring networks for infringement or taking more aggressive actions where unnecessary.

“[T]he directive expressly rules out the adoption of a measure to monitor information transmitted via a given network. Similarly, a measure consisting in terminating the internet connection completely without considering the adoption of measures less restrictive of the connection provider’s freedom to conduct a business would not be capable of reconciling the abovementioned conflicting rights,” the Court concludes.


把螢幕打直 (Landscape to Portrait)

Slashdot 的「The Case For Flipping Your Monitor From Landscape to Portrait」這篇引用了「You've been using your monitor wrong this whole time」這篇文章。

文章裡提到了不少範例,像是 CNN 網站的樣子:

以及 Google 的搜尋結果:


如同 Slashdot 網站上 comment 提到的,我也是一個螢幕打橫一個打直,這樣不同用途用起來比較方便。(看影片時會需要正常的螢幕)

不過我之前有提過,有些網站設計時把寬度最小值設成 1280px,剛好對上 1920x1200 的螢幕打橫後就中獎,這就比較痛苦了:

這篇剛好測試一下 Facebook 的 embed 用在 WordPress 裡面會怎樣 :o


回家發現螢幕過電沒畫面,看了一下購買日期,過三年保固期在討錢了... 只好先把電腦電源關掉,明天下班的時候去光華商場買一顆回來。在新的螢幕到之前只好先用 laptop 撐著。(剛好前陣子買新的 laptop...)

查了一下資料,有支援 2560x1440 WQHD 解析度的只有 AppleDellEIZO 這三家有出,拿來寫 code 偶而看看動畫,應該會買 Dell 的吧...