Bug 110780 - RX 580 and 5K displays, bandwidth validation failed with multiple monitors
Summary: RX 580 and 5K displays, bandwidth validation failed with multiple monitors
Status: NEW
Alias: None
Product: DRI
Classification: Unclassified
Component: DRM/AMDgpu (show other bugs)
Version: unspecified
Hardware: All Linux (All)
: medium major
Assignee: Default DRI bug account
QA Contact:
Depends on:
Reported: 2019-05-28 08:30 UTC by Gaël HERMET
Modified: 2019-08-18 13:58 UTC (History)
3 users (show)

See Also:
i915 platform:
i915 features:


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Description Gaël HERMET 2019-05-28 08:30:23 UTC
I have been facing an issue with my 5K display (iiyama ProLite XB2779QQS-S1).

It works fine as long as it is the only active monitor, as soon as I activate another monitor the main one (5k) can't display more than 4k.

Debug using "echo 0x4 > /sys/module/drm/parameters/debug" show this :
mai 23 09:01:22 bureau-gael /usr/lib/gdm3/gdm-x-session[3465]: (EE) AMDGPU(0): failed to set mode: Invalid argument
mai 23 09:01:22 bureau-gael kernel: [drm:dce112_validate_bandwidth [amdgpu]] dce112_validate_bandwidth: Bandwidth validation failed!

I disabled the check by forcing is_display_configuration_supported to return true in dce_calcs.c and it works fine.

I tried a lot of kernel (includig drm-tip and 5.2-rc1) and they all have the same issue.
My custom kernel with no validation is based on Ubuntu's 5.0.0-15-generic.

If I can help by providing more logs or test something ask and I will do my best.

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