Hi,

I have installed Fedora 23 on my Lenovo W530 ThinkPad. Everything works fine out of the box, even WiFi and Multimedia, all that stuff works great. It is very fast. Top! But I have one ugly thing here. During boot, there is a message shown "*ERROR* PCH transcoder FIFO A underrun". I think this message has something to do with the fact that my ThinkPad has an NVIDIA graphcs card as well as an Intel one. The NVIDIA card is needed for the external display port as well as for the VGA connector. The error doesn't seem to have an impact on the performance of the ThinkPad, I can even connect an external display and that works well, using the nouveau driver.
I already searched the web on this topc, but I only found some old threads from 2014 with no solutions. I wonder whether it is possible to
a) fix this error or
b) hide this specific error message during the boot process (I wolud like to see the boot splash screen instead of some strange and ugly error messages).

What could I do to find out what exactly is causing the problem, and how can I resolve it?

I found a link http://www.annevanrossum.com/blog/20...linux-graphics which explains some of the underlying mechanisms that produce this type of message. It's for intel, not nvidia but you might be able to generalise from it (or maybe it's your intel gpu that's causing it). The problem is with the kernel's drm module. It doesn't provide a solution though.

Hi hazel,
thanks for that interesting link. I wonder whether it is really possible that nobody has a solution to that problem? at least the guy who wrote the drm driver should have an idea how to fix the problem. Is it possible to hide these error messages during boot, e.g. with some GRUB config?

Yes, you can suppress visible kernel messages in general by using the "quiet" option on the kernel command line (they still go into the log files), but I don't think there is any way of selectively suppressing individual ones.

Hi,
I already have the "quiet" option present, as well as rhgb. As far as I know, rhgb is the option I want, because I would like to see the boot splash screen instead of some command line stuff. However, quiet doesn't seem to prevent errors from showing up. Is there some option to make quiet more "restrictive" ?

Hi,

some interesting things to mention:
The W530 has a VGA port for an external screen which is driven by the NVIDIA card. If the external screen is connected before the laptop is powered on, there is NO error message! no FIFO underrun, yeah :-) I guess due to NVIDIA Optimus technology, the Intel graphics chip which causes the FIFO error is disabled.
Interesting thing is: if I do an lspci, I can see both, the NVIDIA as well as the Intel, graphics card. If I disconnect the external screen and reboot, the FIFO error shows up again, and lspci still lists both cards.
This is really weird :-( and no solution seems to be available. I think I am going to compile my own kernel and remove the printk() call which outputs these annoying messages.