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Windows 10 External Video Part 5 – Failure

I’m either very persistent or very stupid. After 4+ months, I’m still chasing unexplained problems with external video on the HP EliteBook x360 1030 G2 laptop that I bought in May. Recently I thought I’d finally solved it, but I was wrong, and now the problem is worse than ever. I am slowly going insane.

For the previous chapters of this story, see part 1, part 2, part 3, and part 4. Here’s a short refresher:

  • Windows 10 laptop with an external monitor, ASUS PB258Q 2560 x 1440
  • works OK during normal use
  • problems appear every couple of days, after a few hours of idle time or overnight
  • random crashes in Intel integrated graphics driver igdkmd64.sys (stopped after upgrading the driver)
  • computer periodically locks up with a blank screen and fan running 100%
  • Start menu periodically won’t open, must kill WindowsShellExperienceHost.exe
  • Windows toolbar sometimes disappears
  • Chrome window sometimes gets resized to a tiny size

This might sound like a random collection of symptoms, but I’m 99% sure they’re all somehow related to the external video. I suspect the external video is periodically disconnecting or crashing or entering a bad state, which causes errors for the Start menu, toolbar, and applications, and sometimes causes the computer to freeze.

 
Updates

Here’s a recap of the past month. On August 15, I switched from using an HDMI cable to a USB-C to DisplayPort cable. This did not fix the problems. On August 22, in the Windows advanced power options, I changed the Intel Graphics Settings power plan when plugged in to “maximum performance”, and also changed the minimum processor state when plugged in to 100%. The computer then went seven days without problems. On August 29, I also installed two “critical” HP updates: a BIOS update and an Intel Management Engine Driver update. Neither one mentioned anything about video issues in its release notes. The computer went a further 11 days without problems – 18 total days problem free!

Believing that the issue was resolved, on September 9 I switched back to an HDMI cable, which I prefer over DisplayPort for reasons of convenience. Within a few hours, the problems returned. I swapped the DisplayPort cable back in, and everything seemed OK.

But this morning, I once again experienced a frozen computer with a blank screen and fans running 100%. After forcing a shutdown and restart, the external monitor via DisplayPort no longer works at all. When I connect the cable, the Device Manager shows “Cable Matters USB-C Video Cable” but no external display is detected. I’ve tried rebooting and unplugging/replugging the cable at both ends, and cycling through options in the monitor’s menus, but nothing helps. Maybe the cable is broken? It was working last night, and I didn’t touch it after that.

 
Where Do We Go From Here?

I’m at wits’ end. Is this is a Window 10 driver problem? Laptop hardware problem? External monitor hardware problem? Cable problem? Multiple such problems at once? The sometimes long delay between problem episodes is frustrating any attempt to find a solution. Typically the problems appear every couple of days, but I recently went 18 days between problem events. That makes it almost impossible to make changes one at a time and draw conclusions about whether they helped.

A few people have suggested I try running Linux, to help determine whether this is a Windows problem or a hardware problem. I have briefly run Linux a few times, and it works OK. But I can’t devote 18+ days to running Linux simply as an experiment. Much of the software that I use is Windows-only, and I’m not interested in switching to Linux as my desktop OS right now.

I could look into repairing or returning the computer, but I’m not interested in that. It was a used/refurb machine, and not terribly expensive. While the money is not insignificant, my time and the disruption to my work are more important. I can’t be without this computer for three weeks while a reseller or PC tech experiments with it. If I need to move everything to another PC anyway, then I’ll simply go with that as the final solution.

I could try another DisplayPort cable. Maybe it simply broke somehow. That would be cheap and easy, and everything did seem OK via DisplayPort up until today.

I could also try switching back to my old 1920 x 1080 external monitor. In earlier testing from June-July, that seemed to work OK, but perhaps I just didn’t test it long enough. Reverting to the smaller and lower-resolution monitor would be a disappointment, but at this point I would be happy with any solution that works.

Finally, I could just replace the whole computer. That’s what I keep threatening to do, but I haven’t yet. Reinstalling and reconfiguring all the software on this PC would be a major pain, and the memory of that experience is still fresh in my mind from May. Several multi-gigabyte packages would need to be downloaded again, and node-locked licenses re-requested and regenerated for several software tools. When I went through the process in May, it took close to a week to get through it all.

Perhaps I could clone the existing hard drive and use it in the new PC, avoiding having to repeat all the software setup. But then I’d also be cloning all the HP-specific drivers and plugins and utilities, while missing out on all the vendor-specific stuff for the new computer. And I’d still need to regenerate the node-locked licenses for some software, even if I didn’t need to download and install them again. Maybe it’s better to start with a clean slate, even if it takes longer.

I know any computer can have hardware problems, and any OS can have bugs. But I can’t escape the feeling that this type of driver/hardware mystery is precisely why so many people dislike Windows. I feel like I’m living in one of those “I’m a Mac, I’m a PC” television commercials. If you have any suggestions for other solutions I could try (short of a sledgehammer), please share them in the comments.

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Wombat Released into the Wild

The Wombat ADB-USB input converter is now back in stock at the BMOW Store. Head there to get yours now.

Wombat what? The Wombat is a bidirectional ADB-to-USB and USB-to-ADB converter for keyboards and mice, and was developed by Steve Chamberlin here at Big Mess o’ Wires. Connect modern USB keyboards and mice to a classic ADB-based Macintosh, Apple IIgs, or NeXT machine. Or connect legacy ADB input hardware to a USB-based computer running Windows, OSX, or Linux. No special software or drivers are needed – just plug it in and go. For more details, please see the product description page.

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Floppy Emu and Disk Daisy Chainer Restock

After a few weeks’ absence, the BMOW Floppy Emu disk emulator for vintage Apple computers is back in stock. Get yours now at the BMOW store. This is the latest version Floppy Emu Model C, with OLED display.

Floppy Emu is a floppy and hard disk emulator for classic Apple II, Macintosh, and Lisa computers. It uses an SD memory card and custom hardware to mimic an Apple floppy disk and drive, or an Apple hard drive. The Emu behaves exactly like a real disk drive, requiring no special software or drivers.

 
Disk Daisy Chainer

The Daisy Chainer adapter for Floppy Emu is now available for public sale, after a long period of limited release. The Daisy Chainer board makes it possible to insert a Floppy Emu anywhere into your daisy chain of Apple II drives, with other floppy drives before and/or after it in the chain. It provides a nice improvement in flexibility for Apple IIGS owners and other Apple II users with complex drive setups.

The Daisy Chainer is a smart device with an onboard microcontroller for decoding the drive enable signals. It automatically senses the type of disk drive connected to its downstream daisy chain port, as well as the current emulation mode of the connected Floppy Emu. Some past blog posts about Daisy Chainer development are available here: part 7, part 6, part 5,
part 4, part 3, part 2, and part 1.

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Windows 10 Crashes Part 4 – 2K Video

I’m still chasing after unexplained errors and crashes with the new Windows 10 powered HP EliteBook x360 1030 G2 laptop that I bought in May. See part 1, part 2, and part 3 for the backstory. The computer crashes, freezes, reboots, or experiences other problems every day or two when I’m not using it – I’ll return to the computer after a few hours and discover that something’s gone wrong. From investigation of event logs and other clues, the problems seem related to the graphics display. I’m using the laptop with an external ASUS PB258Q 2560 x 1440 monitor. On June 15 I uninstalled the HP OEM graphics driver and installed the generic Intel graphics driver, after which I had no more crashes, but I continued to see other problems:

  • computer periodically locks up with a blank screen and fan running 100%
  • computer is unexpectedly off, then hangs during booting
  • Start menu won’t open
  • Windows toolbar is missing
  • Chrome window gets resized to a tiny size

After a few months of testing, I believe I’ve finally isolated the problem: the computer can’t handle 2560 x 1440 graphics on an external monitor. If I use a 1920 x 1080 monitor, or a 2560 x 1440 monitor running at 1920 x 1080 resolution, everything is OK and the computer runs smoothly for weeks at a time. But switch to 2560 x 1440 resolution and problems reappear within a day or two.

What’s going on here? A previous commenter mentioned that for resolutions above 1920 x 1080, HDMI uses a different signalling method with a higher frequency data rate. That’s probably part of the answer, but if there were problems with the faster data rate, I’d expect to see video artifacts rather than Windows errors. I tried two different HDMI cables to see if that might help, but it made no difference. Perhaps the 2560 x 1440 resolution is forcing the integrated graphics hardware to work at a faster rate or in a different mode, exposing some firmware bug or hardware defect, or simply overheating.

As a last-ditch solution, as of today I’m running 2560 x 1440 using a USB-C to DisplayPort cable instead of HDMI. Maybe that will help, maybe not. If it doesn’t eliminate the problems, I’ll have to choose between attempting to RMA the computer or just living with 1920 x 1080 resolution. The lower resolution by itself isn’t so bad, but that solution would leave me with a useless 2K monitor. Anybody interested in some used hardware? 🙂

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ADB-USB Wombat Manufacturing Trouble

Today I received a new batch of Wombat boards from my manufacturing partner. Too bad none of them work! Connected devices aren’t recognized, in either ADB or USB input modes. Oops.

After some lengthy investigation, I discovered that the main crystal oscillator speed on these new boards is about 3.69 MHz, but it should be 8.0 MHz. At 3.69 MHz the board will not work. But the oscillator seems to be an 8 MHz one (at least it has “8.0” in the part number stamped on it), and the associated capacitors and resistors measure roughly the same in-circuit values as a known-good board, so it’s unclear why I’m getting 3.69 MHz oscillation.

Problems happen, but this particular problem should have been caught by the testing procedure that I designed, before the boards were ever shipped to me. I re-ran the test procedure here, using a copy of the test harness that I previously gave to the manufacturer, and sure enough all five of the boards I tried failed the test. So either there’s some discrepancy between how I’m testing and how they’re testing, or they did the tests incorrectly, or didn’t run the tests at all.

The hardware and the test process are identical to the previous three Wombat batches made by the same manufacturer, but the person overseeing the project changed this time.

This is my nightmare scenario, and I’m not sure where to go from here. With some more bench time, I could probably determine exactly why the oscillation speed is 3.69 MHz. Perhaps these boards could be fixed with some hot air rework and component replacement, but who’s going to do that? I’m not about to desolder and replace crystal oscillators on hundreds of boards by hand, to fix someone else’s mistake. Returning the whole batch for rework in China would be prohibitively expensive in shipping and tariff costs. Even if the manufacturer agrees to stump for a complete re-do of the manufacturing, I’ll still be out roughly $750 for the cost of ICs I purchased and provided to them.

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Windows 10 Crashes Part 3 – New Clues

I’ve been struggling with unexplained Windows 10 crashes ever since I got a new computer in May. See part 1 and part 2 for the backstory. The symptoms were mysterious crashes and reboots that happened every day or two when I was not using the computer. From examining crash dumps and event logs, I found that most of the problems seemed related to the graphics display or window manager. I suspected that something about the computer’s handling of my external monitor was buggy – either in the Windows driver, the computer’s firmware, or the computer hardware itself.

I’m now more confident than ever that the external monitor is somehow causing the problem. On July 5, I swapped in a different external monitor and made a few other graphics changes, and since then I’ve gone 11 days with zero crashes or unexplained reboots. Unfortunately this new-and-stable config is not the config I actually want, so I still need to do more testing, but I think I’m getting close to a solution.

The computer is an HP EliteBook x360 1030 G2 laptop. It has a built-in 1920 x 1080 display. A second external monitor is connected by HDMI cable.

The crashes-every-day configuration was an ASUS PB258Q 2560 x 1440 monitor, connected with a no-name HDMI cable, and running at its native resolution. The Windows 10 Display control panel was set to “duplicate”, showing the same image on the external and internal monitor (scaled down). Scaling was set to 125% to make text more legible on the high-DPI external monitor.

The new-and-stable configuration is an ASUS VE228 1920 x 1080 monitor, connected with an Amazon Basics HDMI cable, and running at its native resolution. The Windows 10 Display control panel is set to “show only on 2”, effectively disabling the internal display. Scaling is set to 100%. Everything else is the same as before – same graphics driver version, etc.

Now I can do some A/B testing, and try to determine which of these differences is causing problems. Could it be something as stupid as a bad HDMI cable? Does the computer’s firmware not correctly handle scaling when the external monitor is a different resolution than the internal one? Could the 2560 x 1440 monitor actually cause crashes somehow, due to a bug in its firmware (I think HDMI is bidirectional) or electrical faults?

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