[SOLVED]H170 boot issue when CSM is disabled

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   Hi
I am trying to boot with CSM disabled.  Motivations and what I am experiencing are similar to OP in this post.

I can disable CSM and then successfully restart and also boot from cold.  However, if I leave the machine for any length of time (hours, over night say), then when I cold boot, I get 5 beeps (AIUI this means failure to init video).  The machine then restarts of its own accord, having re-nabled CSM itself.  All other UEFI/BIOS customisations seemed to be preserved.

I would like to have CSM off as I have discovered that, without it,  my displayport monitor switches on immediately and I can see boot managers etc with out resetting the machine straight after a cold boot.  Plus, it would be good to go pure UEFI as I do not appear to need legacy/BIOS support.
I am sure the installed OS are UEFI mode and the graphics (which the beeps indicate are the culprit) should have a GOP VBIOS provided in the ASROCK UEFI for this board:

Asrock H170M PRO4
BIOS 7.1
CPU i5-6600
No discrete graphics in use, I have BIOS set to init built in IGPU first.

Advice and suggestions much appreciated.

Many thanks.

Edited by keeka - 04 Nov 2017 at 2:37pm

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keeka Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 22 Dec 2015 Status: Offline Points: 50	Post Options Post Reply Quote keeka Report Post Thanks(0) Quote Reply Topic: [SOLVED]H170 boot issue when CSM is disabled Posted: 03 Nov 2017 at 11:53pm
	Hi I am trying to boot with CSM disabled. Motivations and what I am experiencing are similar to OP in this post. I can disable CSM and then successfully restart and also boot from cold. However, if I leave the machine for any length of time (hours, over night say), then when I cold boot, I get 5 beeps (AIUI this means failure to init video). The machine then restarts of its own accord, having re-nabled CSM itself. All other UEFI/BIOS customisations seemed to be preserved. I would like to have CSM off as I have discovered that, without it, my displayport monitor switches on immediately and I can see boot managers etc with out resetting the machine straight after a cold boot. Plus, it would be good to go pure UEFI as I do not appear to need legacy/BIOS support. I am sure the installed OS are UEFI mode and the graphics (which the beeps indicate are the culprit) should have a GOP VBIOS provided in the ASROCK UEFI for this board: Asrock H170M PRO4 BIOS 7.1 CPU i5-6600 No discrete graphics in use, I have BIOS set to init built in IGPU first. Advice and suggestions much appreciated. Many thanks. Edited by keeka - 04 Nov 2017 at 2:37pm

keeka Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 22 Dec 2015 Status: Offline Points: 50	Post Options Post Reply Quote keeka Report Post Thanks(0) Quote Reply Posted: 04 Nov 2017 at 2:36pm
	Seems the monitor must be powered up when the PC boots in UEFI mode (CSM disabled). I use an APC BACK-UPS, which cuts power to the peripherals when the PC switches off. Seems that the monitor is not quite ready in time, when the PC boots, for the video BIOS to consider the monitor available over DPP. I have plugged the monitor in to a mains socket independent of the UPS's and the machine boots fine. Edited by keeka - 04 Nov 2017 at 3:03pm