{"id":28009,"date":"2020-02-03T15:51:30","date_gmt":"2020-02-03T20:51:30","guid":{"rendered":"https:\/\/mjtsai.com\/blog\/?p=28009"},"modified":"2020-02-26T15:07:44","modified_gmt":"2020-02-26T20:07:44","slug":"macos-display-problems","status":"publish","type":"post","link":"https:\/\/mjtsai.com\/blog\/2020\/02\/03\/macos-display-problems\/","title":{"rendered":"macOS Display Problems"},"content":{"rendered":"

Lloyd Chambers<\/a>:<\/p>\n

After every reboot, the LG 5K display goes to maximum brightness.<\/p><\/blockquote>\n\n

John Gruber<\/a>:<\/p>\n

\n

Is this the worst bug in the world? Not even close. It’s a paper-cut bug. No data loss, no crash, not something sort of thing where something doesn’t even work — just an annoyance. But no one wants to use a tool that gives you half dozen paper cuts every day. And MacOS 10.15 is chockablock with paper-cut bugs.<\/p>\n<\/blockquote>\n\n

I don’t have an LG 5K, but I’ve been having problems with multiple external displays ever since getting a USB-C Mac. Sometimes the Mac sees the external display, and puts windows on it, but the display itself shows only black (yet isn’t asleep). Rebooting the Mac doesn’t help. Shutting down the Mac and unplugging\/replugging the display doesn’t help. Rebooting the Mac without the display and then shutting down and plugging it in doesn’t help. The only thing that seems to help is swapping the display to another USB-C port—thankfully, I have more than one. Then, a while later, the problem repeats and I have to switch back to the first USB-C port.<\/p>\n\n

Craig Hockenberry<\/a>:<\/p>\n

\n

My 16” MBP is waking itself up hundreds of times overnight, probably with the display on. Catalina is draining about 1\/4 of the battery because of it.<\/p>\n<\/blockquote>\n\n

Maxwell Swadling<\/a>:<\/p>\n

\n

The strangest bug with Apple’s USB-C stack is power saving will happily put the display to sleep, which disables USB hub power, causing force ejection of any external drives you have, potentially corrupting them.<\/p>\n<\/blockquote>\n\n

Simon Wolf<\/a>:<\/p>\n

\n

Any chance this is why external monitors cause a watchdog panic and reboot when my iMac sleeps under Catalina? I’ve heard that external drives can cause it too.<\/p>\n<\/blockquote>\n\n

John Gruber<\/a>:<\/p>\n

\n

I didn’t even mention it in my post, but I’d say about 1 in 10 times I open my 16-inch MBP, the built-in display contrast is waaaaay off. Way too much contrast. I can fix it either by moving brightness all the way down then back up again, or by closing and reopening the lid.<\/p>\n<\/blockquote>\n\n

Peter Steinberger<\/a>:<\/p>\n

\n

The LG 5K is C U R S E D<\/p>\n

We bought 10 for the company and it was the single dumbest hardware purchase decision I ever made.<\/p>\n<\/blockquote>\n\n

Howard Oakley<\/a>:<\/p>\n

\n

An external display can be a good way of adding more USB-C ports to a Mac, but a strange bug can cause a lot of trouble with this otherwise excellent solution.<\/p>\n

As I wrote back in November<\/a> last year, letting an external display sleep can precipitate a kernel panic or other problem when the display goes to sleep, or the Mac tries to wake it up.<\/p>\n<\/blockquote>\n\n

Lloyd Chambers<\/a>:<\/p>\n

But it is much worse than I realized: when I reboot<\/strong> after some time, Crapalina 10.15.3:<\/p>