Intel UHD 630 Graphics eDP pixel clock limits

[myth]

Hello,

I have an Intel i7 9750h UHD 630 laptop with 1440p 165hz display. According to the intel datasheet the uhd 630 video card supports HBR2 via eDP port.

According to the display port 1.2 specifications, 8 bpc 720mhz or 17.28Gbps data transfer can be done with HBR2.

But I can't reach these values on my computer.

When I edit my monitor edid information, the pixel clock limited to 655.35 mhz in the Intel driver detailed resolution section, but if I add a resolution in the DisplayID 1.3 extension block, I can reach up to about 668mhz pixel clock limit.

According to the original edid data of my display, it works at 704mhz, but I can't use it without editing edid because I can't go up to this value.

My question is why there is a limit of 655.35 mhz and how did I exceeded this limit with the displayID extension block? And why can't I go above a 668 mhz? Isn't the limit supposed to be 720mhz?

I have attached some explanatory pictures below.

[MUC]

These are the Video Electronics Standards Association (VESA) parameters for Coordinated Video Timing - Reduced Blanking (CVT-RB):

	v1	v2
Aspect Ratio	16:9	16:9
Pixel Clock	699.5	679.1	MHz
H Active	2560	2560	Pixels
H Front Porch	48	8	Pixels
H Sync	32	32	Pixels
H Back Porch	80	40	Pixels
H Sync Polarity	Positive	Positive
H Freq	257.169	257.235	kHz
V Active	1440	1440	Lines
V Front Porch	3	105	Lines
V Sync	5	8	Lines
V Back Porch	111	6	Lines
V Sync Polarity	Negative	Negative
V Freq	164.958	165	Hz

Your laptop display appears to require custom timings, which may only be possible in the driver that the laptop manufacturer has customized. Are you using the laptop manufacturer's driver or the generic Intel driver?

[myth]

CVT-RB2 is 679.1 mhz pixel clock. But my display not working when i try bigger then 668mhz pixel clock. I am using latest driver from intel right now which is (31.0.101.2125) also tried with OEM drivers but still stuck at 60hz. I want to use my monitor without editing custom timings. I dont understand why my limit is 668 mhz while HBR2 supported ?

[MUC]

Could you please specify the laptop model?

[myth]

MSI GL65 9SE Its not my stock display i just changed, it supposed to work but it doesn't.

[MUC · Accepted solution]

So you're trying to put a BOE laptop display into operation. The MSI GL65 9SE-225 device originally has a display with 1920 × 1080 @ 120 Hz, which according to the system circuit diagram above is connected to the Intel Coffee Lake GT2.

Intel UHD Graphics 630 is stated as shown in one of your screenshots with a maximum of 4096 × 2304 @ 60 Hz 8 bpc (= 2560 × 1440 @ 144 Hz) >>> 605 MHz Pixel Clock (CVT-RB v1). This is probably the tested and released limit. Since the required pixel clock is above the Intel specs, it is probably due to limitations in the drivers, neither of which were designed for your new display, even if the maximum is theoretically 720 MHz pixel clock. I don't think there's anything you can do here.

[myth]

Thank you for your explanations. I also didn't know that my DisplayPort is directly connected to the external gpu, which is good for me.

Apart from that, I share below some data I found for who are interested in this subject.

There are many 10th generation core processor devices sold in the market with 1440p 165hz panel. When I look at the specifications of these panels, the pixel clock values are at maximum 667 - 668 mhz. Unlike to the maximum value mentioned in the Intel datasheet, 668 mhz value can be reached. I can confirm this with my own device and a few other devices that I have tested.

Long story short, 668 mhz seems to be the real pixel clock limit for eDP in devices for the 9th and 10th generation. Since there is no software/mod that can exceed this value for now, there is nothing we can do.