AM5 big performance reduction with CSM boot mode and Wi-Fi disabled.

AM5 big performance reduction with CSM boot mode and Wi-Fi disabled.

[Mohammad Hosain]

Hello
There is a big performance bug (only affecting games performance) on Linux (not reproducible on Windows) with AM5 boards (at least for my MSI MAG b650 Tomahawk) if these BIOS settings are used:
CSM -> Enabled
Wi-Fi -> Disabled (or set to Bluetooth only)
This does not happen even on Win 7... (I've only tested DX12 games) and does not happen if UEFI mode is chosen. I've tested with many different BIOS versions all showing the same result.
I have tried troubleshooting with MSI with some benchmarks posted (https://forum-en.msi.com/index.php?threads/b650-tomahawk-bios-bug-disabling-wi-fi-massively-reduces-system-performance.396910/) and after a week we realized this only happens on Linux (tested on Arch/Fedora/Ubuntu with 6.8 and 6.9 kernels for the first two).
Please investigate. 
Thank you

Re: AM5 big performance reduction with CSM boot mode and Wi-Fi disabled.

[Greg KH]

On Thu, May 30, 2024 at 09:37:18AM +0000, Mohammad Hosain wrote:
> Hello
> There is a big performance bug (only affecting games performance) on Linux (not reproducible on Windows) with AM5 boards (at least for my MSI MAG b650 Tomahawk) if these BIOS settings are used:
> CSM -> Enabled
> Wi-Fi -> Disabled (or set to Bluetooth only)
> This does not happen even on Win 7... (I've only tested DX12 games) and does not happen if UEFI mode is chosen. I've tested with many different BIOS versions all showing the same result.
> I have tried troubleshooting with MSI with some benchmarks posted (https://forum-en.msi.com/index.php?threads/b650-tomahawk-bios-bug-disabling-wi-fi-massively-reduces-system-performance.396910/) and after a week we realized this only happens on Linux (tested on Arch/Fedora/Ubuntu with 6.8 and 6.9 kernels for the first two).

Is this a regression?  If so, what kernel version worked?  What did not
work?  Can you use 'git bisect' to find the problem?

And if it a regression, please report it to the regression list AND the
developers for the subsystem involved.

If it isn't a regression, perhaps it never has worked?

thanks,

greg k-h

Re: AM5 big performance reduction with CSM boot mode and Wi-Fi disabled.

[Mohammad Hosain]

I think it has never worked (I remember as back as 6.7 it behaved like this but only recently I discovered it). If you enable CSM and disable Wi-Fi using BIOS, gaming performance is massively reduced on AM5 boards... This only happens on Linux.

I don't know who are the developers involved that is why I emailed stable@vger.kernel.org.

Thank you.






On Thursday, May 30, 2024 at 04:19:22 PM GMT+3:30, Greg KH <gregkh@linuxfoundation.org> wrote: 





On Thu, May 30, 2024 at 09:37:18AM +0000, Mohammad Hosain wrote:

> Hello
> There is a big performance bug (only affecting games performance) on Linux (not reproducible on Windows) with AM5 boards (at least for my MSI MAG b650 Tomahawk) if these BIOS settings are used:
> CSM -> Enabled
> Wi-Fi -> Disabled (or set to Bluetooth only)
> This does not happen even on Win 7... (I've only tested DX12 games) and does not happen if UEFI mode is chosen. I've tested with many different BIOS versions all showing the same result.
> I have tried troubleshooting with MSI with some benchmarks posted (https://forum-en.msi.com/index.php?threads/b650-tomahawk-bios-bug-disabling-wi-fi-massively-reduces-system-performance.396910/) and after a week we realized this only happens on Linux (tested on Arch/Fedora/Ubuntu with 6.8 and 6.9 kernels for the first two).


Is this a regression?  If so, what kernel version worked?  What did not
work?  Can you use 'git bisect' to find the problem?

And if it a regression, please report it to the regression list AND the
developers for the subsystem involved.

If it isn't a regression, perhaps it never has worked?

thanks,

greg k-h

Re: AM5 big performance reduction with CSM boot mode and Wi-Fi disabled.

[Greg KH]

On Thu, May 30, 2024 at 04:59:12PM +0000, Mohammad Hosain wrote:
> I think it has never worked (I remember as back as 6.7 it behaved like this but only recently I discovered it). If you enable CSM and disable Wi-Fi using BIOS, gaming performance is massively reduced on AM5 boards... This only happens on Linux.
> 
> I don't know who are the developers involved that is why I emailed stable@vger.kernel.org.

stable@vger is not the correct place for generic bug reports like this,
sorry.  Please try reporting this on the linux wifi mailing list, the
developers there should be able to help you out more.

good luck!

greg k-h