Lost 120Hz on BenQ XL2420Z

Discuss BENQ Blur Reduction (strobe backlight) and the Blur Busters Strobe Utility. For Z-Series monitors (V2 firmware) on XL2411Z, XL2420Z and XL2720Z.

Lost 120Hz on BenQ XL2420Z

Postby senjin » 15 Dec 2016, 22:44

I tried flashing an XL2420Z V1 to V4 with the linux method.

Everything seemed to go fine, no error messages, found the correct bus and chip etc.

But after flashing, during it's verify phase, I got a message that it failed at address 0x00000000 already. Not daring to powercycle, I tried flashing again, this time it all went through. I was away from my screen for a couple of seconds so it seemed though that the actual flashing/writing only lasted a couple of seconds instead of the minutes it took the first time.
I didn't think much of it though as my monitor was flashing colors and showing a message about burn in that I didn't recognise.
So I fiddled with the monitor a bit. Trying to turn it off and on, trying to see if I could get to the information page to see if the flash succeeded and lo and behold V4 was installed.

Reboot back to windows 10.

Now I find that I have 60Hz, 100Hz and 144Hz resolutions available in my Geforce settings. My 120Hz resolutions seem to be missing.
I enter a new custom resolution, forced to 120Hz and the vertical total to 1350 because that's supposed to make my screen a bit brighter as well.

This seems to work slightly. Dark colors are still way too dark using the calibrated icc profiles you can find online.
When I turn on blur reduction in this resolution, the screen turns black. So I can't use that.

If I enter a custom 120Hz resolution without changing the timings, it does seem to work with blur reduction. Only the monitor itself now reports that it's doing 60Hz instead of 120Hz.

Did I mess up my EDID?

I unfortunately don't have a backup. My harddrives were inaccessible from the linux side of things and I gave up trying to get my phone recognised as USB storage after the flash seemed to be fine.

Can I just retry flashing V4 or do I need to reinstall the nvidia drivers perhaps?
Is there a V5 for XL2420Z that might fix things? I heard mention of it, but can't find it anywhere. V4 is the only one I can find for that matter. The BenQ gaming download site takes you to the Zoey page now instead of letting you download any firmware. V2 can't be found anymore so I can't try that either.

I'm also still unclear about that burn-in option. I know now how I can reach the settings page to change it with holding down the 3rd and 4th button simultaneously while tapping power, then using the 5th button to show the burn-in setting. But I got no clue what that does except for changing the color of my power light to orange.

Should I flash with burn-in enabled, would that fix things?

I'm a little worried of messing things up more, so I'm asking here.
senjin
 
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Re: Lost 120Hz on BenQ XL2420Z

Postby Falkentyne » 15 Dec 2016, 23:33

The monitor reporting 60hz when using a custom vertical total is intentional. The strobing persistence system is tied to the vertical total value, as refresh rates are (I assume by the VESA standard) established with certain VT values.

When a VT value is used that the monitor does not identify as belonging to a preset refresh rate, it reverts to the 60hz persistence values (0.167ms pulse widths per point of Strobe Duty; 0.167 x 100 = 16.7ms (the frame time for 60hz).

I "believe' this reporting behavior (in the OSD at least) was corrected in the XL2430T, but that's not the point (it still uses the 60hz values when at an unknown VT is active, like 1350, 1354, 1500, etc).

120hz missing from the EDID is an issue with Linux and some motherboard Bioses apparently. You were lucky that only 120hz vanished; some people have everything except 60hz vanish and then the monitor get reported as a "generic non PNP monitor." For some reason, some people have the EDID wind up completely corrupted and only get 60hz, but it hasn't been proven conclusively why. This is most likely an issue with Linux itself and how it talks to some motherboards' EFI/UEFI most likely. A 100% way to fix this issue is to use the mstar ISP flash device (VGA or DVI) or the RT809F flasher (VGA only), as that will flash the firmware with the hardware supplied.

http://www.yoycart.com/Product/52781882 ... ment_tool/ or the RT809F flasher can flash the monitors also (I have them both, because reasons).
Falkentyne
 
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Re: Lost 120Hz on BenQ XL2420Z

Postby senjin » 16 Dec 2016, 02:24

I indeed have an UEFI bios. And I had read it could give issues. But since I was initially planning on making a backup, I wasn't all too worried.
Also during boot-selection to linux, it gave me the option to boot the usb stick directly or through uefi. Which I didn't do and hoped would disable uefi. Guess it doesn't.

Maybe I shouldn't have ventured down this update path at all. I don't really care for the blur reduction. All I wanted was to use the icc profiles that you find online and then get my brightness up. Since the pages I found mentioned you could up the brightness with the 1350 trick. And the pages explaining the 1350 trick also mentioned using the strobe tool, that's why I went through the upgrade route.
Now it doesn't even seem that it has made all that much of a difference in my brightness. I'll just have to resort to not using the icc profiles when wanting to game.

So I won't be fiddling with this anymore. Worried of losing even more frequencies. I won't be buying a 50 euro dongle to reprogram my single monitor. I'll just add and use a custom resolution at 120Hz for when I need it. I'm at 144 most of the time anyways.

Thanks for the help. Shame this stuff can't be made a little easier / fault- / dummy-proof. Except for with hardware. I'm familiar with Linux and have experience flashing phones, cdrom drives and other devices over usually usb. But even I was a little nervous doing this. And not without reason it seems.
senjin
 
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Re: Lost 120Hz on BenQ XL2420Z

Postby senjin » 16 Dec 2016, 02:37

Hold your horses...

Lol

I feel so stupid.

The 120Hz option was missing, because I had set up the custom 120Hz resolution with the alternate vertical timings. It displays that one as 'Custom', and removes the 120Hz option from the default PC resolutions. Here I thought it'd just add a custom resolution/timing and not 'replace'. NVidia should've been a bit more clear about that.

Found out about it because I finally decided to remove the custom 120Hz resolution and lo and behold, there was the 120Hz option again. It was also always still available for other non-1920x1080 resolutions, but I hadn't checked those.

So it seems everything worked out after all.

Thanks again and sorry for wasting your time.
senjin
 
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Re: Lost 120Hz on BenQ XL2420Z

Postby senjin » 16 Dec 2016, 02:42

So the only 'issue' remaining is that my screen blanks if I use blur reduction at 120Hz with a 1350 vertical total.
At 120Hz, default vertical total, it works fine.
senjin
 
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Re: Lost 120Hz on BenQ XL2420Z

Postby Falkentyne » 16 Dec 2016, 09:42

The strobe phase is too high. 120hz with VT applied cannot exceed phase 049.
Monitor defaults to phase 100 after a firmware flash.
Falkentyne
 
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