FS#43848 - [linux] FIFO underrun ERROR msg moving to DEBUG mode.

Attached to Project: Arch Linux
Opened by Tomasz Przybył (FadeMind) - Monday, 16 February 2015, 22:02 GMT
Last edited by Bartłomiej Piotrowski (Barthalion) - Tuesday, 11 August 2015, 17:37 GMT
Task Type Feature Request
Category Packages: Core
Status Closed
Assigned To Tobias Powalowski (tpowa)
Thomas Bächler (brain0)
Architecture All
Severity Low
Priority Normal
Reported Version
Due in Version Undecided
Due Date Undecided
Percent Complete 100%
Votes 4
Private No


Since kernel 3.15.1 in dmesg and in boot screen was showed : [drm:cpt_serr_int_handler] *ERROR* PCH transcoder A FIFO underrun.
Reference: https://bugs.archlinux.org/task/40952

This warning is since 3.19 kernel:

[drm:intel_set_pch_fifo_underrun_reporting [i915]] *ERROR* uncleared pch fifo underrun on pch transcoder A
[drm:intel_pch_fifo_underrun_irq_handler [i915]] *ERROR* PCH transcoder A FIFO underrun

and it is annoying.

On Linux 3.19 kernel this warning can be hidden in DEBUG mode after apply patch (in attachment).

This task depends upon

Closed by  Bartłomiej Piotrowski (Barthalion)
Tuesday, 11 August 2015, 17:37 GMT
Reason for closing:  Upstream
Additional comments about closing:  This is an upstream issue and changing log level obviously fixes nothing.
Comment by sven (commonuser) - Wednesday, 29 April 2015, 21:05 GMT Comment by WhiteHat (WhiteHatHacker1) - Wednesday, 15 July 2015, 00:19 GMT
I can confirm that this still happens on my system which has the 4.1.2 kernel.
This bug might be related to https://bugs.archlinux.org/task/40952 .
Comment by f3bruary (f3bruary) - Thursday, 16 July 2015, 12:54 GMT
Confirmed on 4.1.2-2-ARCH
Comment by sven (commonuser) - Thursday, 16 July 2015, 13:06 GMT
What GPU's do you have? It works fine for me on a T420 with SandyBridge.
Comment by f3bruary (f3bruary) - Thursday, 16 July 2015, 14:12 GMT
I run integrated graphics (intel hd4000)
Comment by Tomasz Przybył (FadeMind) - Thursday, 16 July 2015, 14:47 GMT
This issue affects Intel users. Mostly Sandy and Ivy Bridge GPU Family. It is present in kernel since 3.15 release. Like it is in description. Daniel Vetter extract management for FIFO issues in this file:


Patch from this  FS#43848  just hidding warnings in debug mode.
Reference: https://bugzilla.kernel.org/show_bug.cgi?id=79261

Reference in MANs: