Nvidia maximum pixel clock issue in kmod-nvidia-384.98

On CentOS 7 I’m running into an issue with the 384.98 nvidia driver. The driver is downloaded directly from the nvidia driver page. This driver version seem to introduce issue in detecting video modes when a monitor is connected using DVI. As soon as the machine attempts to start X, nothing happens and the monitor goes into sleep mode reporting that it has ‘no signal’.

It is interesting because it occurs with several monitors, but only when they are connected through DVI. When using VGA it works like a charm. Also it did work without problems with the previous driver version
(384.90), with the exact same setup.

In this case the issue occurs with an Nvidia NVS 315. Other users reported similar issues when using an NVS 315, but so far it doesn’t seem to occur with geforce cards. (not sure about other NVS cards, haven’t tested that)
For reference: [CentOS] Gtkcdlabel + cdlabelgen on CentOS 7 ?

The following information from Xorg.0.log seems of interest:

[   130.447] (--) NVIDIA(0): Valid display device(s) on GPU-0 at PCI:1:0:0
    [   130.447] (--) NVIDIA(0):     CRT-0
    [   130.447] (--) NVIDIA(0):     CRT-1
    [   130.447] (--) NVIDIA(0):     DFP-0 (boot)
    [   130.447] (--) NVIDIA(0):     DFP-1
    [   130.447] (--) NVIDIA(0):     DFP-2
    [   130.447] (--) NVIDIA(0):     DFP-3
    [   130.448] (II) NVIDIA(0): NVIDIA GPU NVS 315 (GF119) at PCI:1:0:0 (GPU-0)
    [   130.448] (--) NVIDIA(0): Memory: 1048576 kBytes
    [   130.448] (--) NVIDIA(0): VideoBIOS: 75.19.88.00.0b
    [   130.448] (II) NVIDIA(0): Detected PCI Express Link width: 16X
    [   130.462] (--) NVIDIA(GPU-0): CRT-0: disconnected
    [   130.462] (--) NVIDIA(GPU-0): CRT-0: 400.0 MHz maximum pixel clock
    [   130.462] (--) NVIDIA(GPU-0):
    [   130.467] (--) NVIDIA(GPU-0): CRT-1: disconnected
    [   130.467] (--) NVIDIA(GPU-0): CRT-1: 400.0 MHz maximum pixel clock
    [   130.467] (--) NVIDIA(GPU-0):
    [   130.488] (--) NVIDIA(GPU-0): Philips 240S4 (DFP-0): connected
    [   130.488] (--) NVIDIA(GPU-0): Philips 240S4 (DFP-0): Internal TMDS
    [   130.488] (--) NVIDIA(GPU-0): Philips 240S4 (DFP-0): 0.0 MHz
maximum pixel clock
    [   130.488] (--) NVIDIA(GPU-0):
    [   130.493] (--) NVIDIA(GPU-0): DFP-1: disconnected
    [   130.493] (--) NVIDIA(GPU-0): DFP-1: Internal TMDS
    [   130.493] (--) NVIDIA(GPU-0): DFP-1: 0.0 MHz maximum pixel clock
    [   130.493] (--) NVIDIA(GPU-0):
    [   130.493] (--) NVIDIA(GPU-0): DFP-2: disconnected
    [   130.493] (--) NVIDIA(GPU-0): DFP-2: Internal DisplayPort
    [   130.493] (--) NVIDIA(GPU-0): DFP-2: 480.0 MHz maximum pixel clock
    [   130.493] (--) NVIDIA(GPU-0):
    [   130.493] (--) NVIDIA(GPU-0): DFP-3: disconnected
    [   130.493] (--) NVIDIA(GPU-0): DFP-3: Internal DisplayPort
    [   130.493] (--) NVIDIA(GPU-0): DFP-3: 480.0 MHz maximum pixel clock
    [   130.493] (--) NVIDIA(GPU-0):
    [   130.493] (EE) NVIDIA(GPU-0): Unable to add conservative
default mode "nvidia-auto-select".
    [   130.493] (EE) NVIDIA(GPU-0): Unable to add
"nvidia-auto-select" mode to ModePool.
    [   130.493] (==) NVIDIA(0):
    [   130.493] (==) NVIDIA(0): No modes were requested; the default
mode "nvidia-auto-select"
    [   130.493] (==) NVIDIA(0):     will be used as the requested mode.
    [   130.493] (==) NVIDIA(0):
    [   130.493] (WW) NVIDIA(0): No valid modes for
"DFP-0:nvidia-auto-select"; removing.
    [   130.493] (WW) NVIDIA(0):
    [   130.493] (WW) NVIDIA(0): Unable to validate any modes; falling
back to the default mode
    [   130.493] (WW) NVIDIA(0):     "nvidia-auto-select".
    [   130.493] (WW) NVIDIA(0):
    [   130.493] (WW) NVIDIA(0): No valid modes for
"DFP-0:nvidia-auto-select"; removing.
    [   130.493] (EE) NVIDIA(0): Unable to use default mode
"nvidia-auto-select".
    [   130.493] (EE) NVIDIA(0): Failing initialization of X screen 0

The log shows “0.0 MHz maximum pixel clock” for the DVI connections.
When enabling ModeDebug in the xorg.conf it shows that all of the
resolutions are rejected because of incorrect maximum pixel clock:

[  1354.589] (II) NVIDIA(GPU-0):
    [  1354.589] (II) NVIDIA(GPU-0): --- Building ModePool for Philips
240S4 (DFP-0) ---
    [  1354.589] (WW) NVIDIA(GPU-0):   Validating Mode "1920x1200_60":
    [  1354.589] (WW) NVIDIA(GPU-0):     Mode Source: EDID
    [  1354.589] (WW) NVIDIA(GPU-0):     1920 x 1200 @ 60 Hz
    [  1354.589] (WW) NVIDIA(GPU-0):       Pixel Clock      : 154.00 MHz
    [  1354.589] (WW) NVIDIA(GPU-0):       HRes, HSyncStart : 1920, 1968
    [  1354.589] (WW) NVIDIA(GPU-0):       HSyncEnd, HTotal : 2000, 2080
    [  1354.589] (WW) NVIDIA(GPU-0):       VRes, VSyncStart : 1200, 1203
    [  1354.589] (WW) NVIDIA(GPU-0):       VSyncEnd, VTotal : 1209, 1235
    [  1354.589] (WW) NVIDIA(GPU-0):       Sync Polarity    : +H -V
    [  1354.589] (WW) NVIDIA(GPU-0):     Mode is rejected: PixelClock
(154.0 MHz) too high for
    [  1354.589] (WW) NVIDIA(GPU-0):     Display Device (Max: 0.0 MHz).
    [  1354.589] (WW) NVIDIA(GPU-0):     Mode "1920x1200_60" is invalid.

Note that with the previous driver (version 384.90), a valid value was
detected for the ‘maximum pixel clock’:

[   124.804] (--) NVIDIA(GPU-0): Philips 240S4 (DFP-0): connected
    [   124.804] (--) NVIDIA(GPU-0): Philips 240S4 (DFP-0): Internal TMDS
    [   124.804] (--) NVIDIA(GPU-0): Philips 240S4 (DFP-0): 165.0 MHz
maximum pixel clock

Since it did work with driver 384.90 and stopped working with version
384.98, it looks like a regression in the nvidia driver.

I tried the short lived 387.34 release and surprisingly the issue didn’t occur anymore.

Is this an issue that was already found in the 384.98 version and therefore resolved?
Is worth reporting this anyway, since the 384.98 is still the latest long lived release?

For completeness: this issue is actually solved in the new driver 384.111 released last Friday. So by now it is already solved in the long-lived release.