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What do I need to modify to add a custom resolution?
11-03-2019, 10:58 PM
Post: #2
RE: What do I need to modify to add a custom resolution?
Well the first problem I see is CRU is not reading the extension blocks, which has the topology information needed to make the two streams work as one display. What video card do you have?

The second problem is since the monitor uses two streams, it should appear as two active displays in CRU, so each display would need to be 3840x4320 instead of 7680x4320, which the monitor already has defined in the extension blocks that you can't see, so there's no point in adding the same resolutions.

The third problem is your bandwidth calculations are wrong. Two DisplayPort 1.4 HBR3 streams gives 64.8 Gbps, but DisplayPort uses 8b/10b coding, so that gives a data rate of 51.84 Gbps. The data rate includes blanking, so you need to calculate with the totals, which in your screenshot is 8240x4410. Also, bits always use multiples of 1000, not 1024 like bytes.

8240 * 4410 * 60 Hz * 30-bit / 1000^3 = 65.40912 Gbps
8240 * 4410 * 60 Hz * 24-bit / 1000^3 = 52.327296 Gbps

You need to reduce the blanking just to get 24-bit to fit, so 30-bit has no chance.

The Dell UP3218K uses two streams at 4040x4368:

2 * 4040 * 4368 * 60 Hz * 24-bit / 1000^3 = 50.8225536 Gbps
2 * 4040 * 4368 * 48 Hz * 30-bit / 1000^3 = 50.8225536 Gbps

That barely fits within the data rate.
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RE: What do I need to modify to add a custom resolution? - ToastyX - 11-03-2019 10:58 PM

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