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PC Drivers & Software

trenzterra
Adept I

My Lenovo ThinkPad X13's display is showing as 6-bit color in Windows

Hi there,

I have a Lenovo ThinkPad X13 (AMD) which I purchased recently, with the touchscreen option (AU Optronics B133HAK02.2). Based on information on the net, this model is ostensibly a 8-bit panel (or perhaps 6-bit FRC?).

In either case, normally, I would expect Windows to report the panel as being a 8-bit panel (it does so for my Dell U2417H when connected to the laptop, even though it is a 6-bit FRC panel). However, I noted that Windows shows the bit depth as 6-bit color when I go to "View advanced display options". There does not seem to be any option to toggle 8bpc in the Radeon Settings control panel (I have downloaded the latest drivers just to be sure).

Initially, I thought "okay, maybe this is just a reporting error, or perhaps this is how AMD reports it to Windows", but this classification as a 6-bit panel seems to have some repercussions. Namely, whenever I view a solid, dark-coloured background (e.g. grey), the solid colour instead appears noticeably grainy, much like a JPEG or MPEG compression artifact. I suspect it is the graphics driver trying to dither the colour (in a very poor manner).

For a while, I was resigned that this is a permanent characteristic of my panel and I would just have to deal with it. However, I got an idea today to boot up to an Ubuntu live CD, and lo and behold! I did not notice any dithering artifacts there and all my solid colours appear, well, solid. I went to the store to test a ThinkPad X13 (Intel version) with the same display panel and it also displays solid colours properly.

Thus, I am inclined to think that there is a bug in the current AMD drivers and that the panel should be reported as an 8-bit panel (and perhaps, if it's 6-bit + FRC, let the monitor do the dithering on its own?). Is there any way this issue could be looked into? Is there also a way to force AMD to display 8-bit colour in Windows and stop dithering my colours?

I am not sure if I have posted in the correct forum, but since there is no laptop forum over here I thought this would be the most appropriate place to post.

Thanks so much!

1 Solution

The true situation is a bit silly.

I dug into the EDID data and it seems that Lenovo is disclosing the panel as a 6 bit display, which is quite unusual, because my Dell U2417H monitor, which is 6 bit plus FRC, discloses itself as an 8 bit panel.

Now the other issue is that the AMD display drivers, for some reason, doesn't bother to probe further and assumes that it is just a "stupid" 6 bit display and dithers everything to 8 bit but disallows FRC on the laptop panel from working its magic. Now what I cannot wrap my head around is, when I trick the drivers to believing that the laptop panel is an 8 bit display (by editing EDID), it still does not allow FRC on the laptop panel to work. I have to uninstall the AMD drivers and revert back to the basic display adapter for 6 bit + FRC to work. Maybe there is an EDID setting which I may have overlooked.

View solution in original post

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17 Replies

If it is greyed out and or not an option then I have no idea how you would force it. I would very much suggest you also ask this question to the company that made your device. These user to user forums may not produce an answer and that is a very unique question. I can tell you that if you did not get the driver you are using from Lenovo that may be your issue. AMD drivers from AMD don't have custom changes in them that laptop makers do to the drivers on their end for the products to work right. 

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ThinkPad X13 (Intel) |13 Inch WFH or Business Laptop | Lenovo Canada 

If you have the cheapest 1366x768 display then its TN FRC which is 6-bit RGB

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I have the 1920x1080 display with 72% NTSC/100% sRGB. I suspect it is 6-bit + FRC.

I just corroborated with another user who has the X390 (Intel version) and it is also reported as 6-bit. So I guess it's the panel.

So now what I am suspecting is the FRC algorithm used by AMD (at least in its Windows drivers) is problematic. When I am in Ubuntu, I do not get the dithering effect; I only experience it in Windows...

Certainly, I will see what Lenovo will say but I was also wondering if anyone has had experience in dealing with such issues. For example, is there a way to disable FRC?   

UPDATE: I tried to uninstall the AMD Radeon Graphics and reverted to Microsoft Basic Display Adapter. Now I am getting full 8-bit colours (as reported in Control Panel) and no dithering artifacts. However, this is not a long term solution for me as I then lose brightness control etc.

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trenzterra wrote:

I have the 1920x1080 display with 72% NTSC/100% sRGB. I suspect it is 6-bit + FRC.

 

I just corroborated with another user who has the X390 (Intel version) and it is also reported as 6-bit. So I guess it's the panel.

 

So now what I am suspecting is the FRC algorithm used by AMD (at least in its Windows drivers) is problematic. When I am in Ubuntu, I do not get the dithering effect; I only experience it in Windows...

 

Certainly, I will see what Lenovo will say but I was also wondering if anyone has had experience in dealing with such issues. For example, is there a way to disable FRC?   

 

UPDATE: I tried to uninstall the AMD Radeon Graphics and reverted to Microsoft Basic Display Adapter. Now I am getting full 8-bit colours (as reported in Control Panel) and no dithering artifacts. However, this is not a long term solution for me as I then lose brightness control etc.

The other panels are IPS according to the product page. So they should be 8-bit RGB.

ThinkPad Notebooks-Lenovo Community 

Try your luck on the Lenovo forum, lots of good people there

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That is very helpful, you should report exactly that to Lenovo and AMD support. Report to AMD here:  https://www.amd.com/en/support/contact-email-form

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Thanks! Didn't know there's a way to contact AMD directly. I will do so.

I did more analysis on my own and noted that the panel's EDID indicated it is 6 bit. So I hacked the INF and got it to show 8 bit. The dithering disappeared, but then I got the banding issue typical of non-8 bit displays without dithering. I guess it really is the dithering mechanism that is the issue here.

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Glad to help. I sometimes fear it is by design you don't know how to contact AMD. They burry it several pages deep and the links you have to click are not what I would be looking for if I needed direct contact. I wish they would just put a simple contact AMD on the main page that directly goes to the support form. Instead the contact link goes to a series of pages and link names that IMHO are not as easy to figure out where to go as it should be. 

You could also see if making a custom resolution after the AMD driver is installed might work. Check out this free utility called CRU from Custom Resolution Utility (CRU) 

Good luck to you!

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Thanks. CRU doesn't allow me to configure bit depth so it wasn't of use there.

Anyway to confirm my hypothesis I plugged in my external Dell monitor and set it to 6bpc in the driver settings. Same dithering issue as what I face. Now I'm thinking maybe AMD drivers are not implementing FRC on my laptop's panel for whatever reason. 

The interesting thing on all this is that 8 bit is a default setting in Windows. So something in the AMD driver has to be overriding it making it wrong. 

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The true situation is a bit silly.

I dug into the EDID data and it seems that Lenovo is disclosing the panel as a 6 bit display, which is quite unusual, because my Dell U2417H monitor, which is 6 bit plus FRC, discloses itself as an 8 bit panel.

Now the other issue is that the AMD display drivers, for some reason, doesn't bother to probe further and assumes that it is just a "stupid" 6 bit display and dithers everything to 8 bit but disallows FRC on the laptop panel from working its magic. Now what I cannot wrap my head around is, when I trick the drivers to believing that the laptop panel is an 8 bit display (by editing EDID), it still does not allow FRC on the laptop panel to work. I have to uninstall the AMD drivers and revert back to the basic display adapter for 6 bit + FRC to work. Maybe there is an EDID setting which I may have overlooked.

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Well obviously if the EDID is saying to set it to 6bit then AMD isn't doing anything wrong. The question is though then, why does the monitor work correctly with another OS or even in Windows with the standard driver. None of that makes any logical sense to me, but a lot of stuff is beyond my knowledge level. I know this isn't a pro card but there is an AMD mod here from the pro side that I have seen help with similar issues. He might have a thought on this. Can't hurt to ask, so I will mention him and he should see this thread. fsadough

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Lenovo has an INF for their LCD panels

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Dobbs
Journeyman III

I have the very same problem on my laptop (ASUS TUF505dy) and made a post but nobody replied. The issue started about three weeks back and I started noticing it just after I had an AMD driver update so pretty sure it's AMD-related. I'm stuck with 6-bit on advanced display settings and the only way I get 8-bit back is with the basic Microsoft display or using external monitor. I get a grainy look on any image (even high res image) when I zoom in even if just slightly. Never experienced this before.

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Have you tried reinstalling the Graphics/chipset driver from the Asus site? (I'd reinstall and then try updating to the latest recommended Amd Graphics driver)

"AMD Graphics, Chipset Driver
Version V26.20.12036.4002
370.6 MB
2021/03/24"
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I will try that, thanks

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Hi, I tried your suggestion and unfortunately no luck. Which driver version is installed seems to make no difference as I've tried many. I wonder if it might have something to do with the EDID settings? No idea how to edit those though

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