Drm: mgag200. Video adapter issue with 5.4.0-rc3 ; no graphics

Thomas Zimmermann tzimmermann at suse.de
Fri Nov 8 15:06:54 UTC 2019


Hi

Am 08.11.19 um 13:55 schrieb John Donnelly:
> 
> 
>> On Nov 8, 2019, at 1:46 AM, Thomas Zimmermann <tzimmermann at suse.de> wrote:
>>
>> Hi John
>>
>> Am 07.11.19 um 23:14 schrieb John Donnelly:
>>>
>>>
>>>> On Nov 7, 2019, at 10:13 AM, John Donnelly <john.p.donnelly at oracle.com> wrote:
>>>>
>>>>
>>>>
>>>>> On Nov 7, 2019, at 7:42 AM, Thomas Zimmermann <tzimmermann at suse.de> wrote:
>>>>>
>>>>> Hi John
>>>>>
>>>>> Am 07.11.19 um 14:12 schrieb John Donnelly:
>>>>>> Hi  Thomas ;  Thank you for reaching out. 
>>>>>>
>>>>>> See inline: 
>>>>>>
>>>>>>> On Nov 7, 2019, at 1:54 AM, Thomas Zimmermann <tzimmermann at suse.de> wrote:
>>>>>>>
>>>>>>> Hi John,
>>>>>>>
>>>>>>> apparently the vgaarb was not the problem.
>>>>>>>
>>>>>>> Am 07.11.19 um 03:29 schrieb John Donnelly:
>>>>>>>> Hi,
>>>>>>>>
>>>>>>>> I am investigating an issue where we lose video activity when the display is switched from from “text mode” to “graphic mode” 
>>>>>>>> on a number of  servers using this driver.    Specifically  starting the GNOME desktop. 
>>>>>>>
>>>>>>> When you say "text mode", do you mean VGA text mode or the graphical
>>>>>>> console that emulates text mode?
>>>>>>>
>>>>>>
>>>>>>
>>>>>> I call “text mode” the 24x80  ascii mode ;  - NOT GRAPHICS .       Ie : run-level 3;  So I  guess your term for it is VGA. 
>>>>>
>>>>> Yes.
>>>>>
>>>>>
>>>>>>
>>>>>>
>>>>>>> When you enable graphics mode, does it set the correct resolution? A lot
>>>>>>> of work went into memory management recently. I could imagine that the
>>>>>>> driver sets the correct resolution, but then fails to display the
>>>>>>> correct framebuffer.
>>>>>>
>>>>>>  There is no display at all ;  so there is no resolution  to mention.    
>>>>>>
>>>>>>
>>>>>>
>>>>>>>
>>>>>>> If possible, could you try to update to the latest drm-tip and attach
>>>>>>> the output of
>>>>>>>
>>>>>>> /sys/kernel/debug/dri/0/vram-mm
>>>>>>
>>>>>> I don’t see that file ;   Is there something else I need to do ? 
>>>>>
>>>>> That file is fairly new and maybe it's not in the mainline kernel yet.
>>>>> See below for how to get it.
>>>>
>>>>  I  built your “tip” ;  Still no graphics displayed . 
>>>>
>>>>
>>>>  mount -t debugfs none /sys/kernel
>>>>
>>>> cat /proc/cmdline 
>>>> BOOT_IMAGE=(hd0,msdos1)/vmlinuz-5.4.0-rc6.drm.+ root=/dev/mapper/ol_ca--dev55-root ro crashkernel=auto resume=/dev/mapper/ol_ca--dev55-swap rd.lvm.lv=ol_ca-dev55/root rd.lvm.lv=ol_ca-dev55/swap console=ttyS0,9600,8,n,1 drm.debug=0xff
>>>>
>>>>
>>>> cat  /sys/kernel/dri/0/vram-mm 
>>>>
>>>> In VGA mode :
>>>>
>>>>
>>>> cat  /sys/kernel/dri/0/vram-mm 
>>>> 0x0000000000000000-0x0000000000000300: 768: used
>>>> 0x0000000000000300-0x0000000000000600: 768: used
>>>> 0x0000000000000600-0x00000000000007ee: 494: free
>>>> 0x00000000000007ee-0x00000000000007ef: 1: used
>>>> 0x00000000000007ef-0x00000000000007f0: 1: used
>>>>
>>>>
>>>> In GRAPHICS mode ( if it matters ) 
>>>>
>>>>
>>>> cat  /sys/kernel/dri/0/vram-mm 
>>>> 0x0000000000000000-0x0000000000000300: 768: used
>>>> 0x0000000000000300-0x0000000000000600: 768: used
>>>> 0x0000000000000600-0x00000000000007ee: 494: free
>>>> 0x00000000000007ee-0x00000000000007ef: 1: used
>>>> 0x00000000000007ef-0x00000000000007f0: 1: used
>>>> total: 2032, used 1538 free 494
>>>>
>>
>> This is interesting. In the graphics mode, you see two buffers of 768
>> pages each. That's the main framebuffers as used by X (it's double
>> buffered). Then there's a free area and finally two pages for cursor
>> images (also double buffered). That looks as expected.
>>
>> The thing is that in text mode, the areas are allocated. But the driver
>> shouldn't be active, so the file shouldn't exist or only show a single
>> free area.
>>
> 
>       If you want me to double check this I will .    I have GNOME installed , but the machine boots to runlevel  3, then I start the desktop using init 5  I am pretty sure I took that output when the machine was in graphic’s mode   at runlevel 5 . 
> 
> 
>>
>>>>
>>>>
>>>>
>>>>>
>>>>>
>>>>>>
>>>>>> I’ve attached : var/lib/gdm/.local/share/xorg/Xorg.0.log. ;   instead ; 
>>>>>
>>>>> Good! Looking through that log file, the card is found at line 79 and
>>>>> the generic X modesetting driver initializes below. That works as expected.
>>>>>
>>>>> I notices that several operations are not permitted (lines 78 and 87). I
>>>>> guess you're starting X from a regular user account? IIRC special
>>>>> permission is required to acquire control of the display. What happens
>>>>> if you start X as root user?
>>>>
>>>>
>>>>   I am starting GNOME  as  root by doing  “init 5” from either the console  session or from ssh .
>>>>
>>>>  The default runlevel is 3  on boot .
>>>>
>>>> On failing session  running  your 5.4.0.rc6.
>>>>
>>>> 78 [   237.712] xf86EnableIOPorts: failed to set IOPL for I/O (Operation not permitted)
>>>>
>>>> 87 [   237.712] (EE) open /dev/fb0: Permission denied
>>>>
>>>> Booting 4.18 kernel yields the same error results in: /var/lib/gdm/.local/share/xorg/Xorg.0.log
>>>>
>>>> 78 [   101.334] xf86EnableIOPorts: failed to set IOPL for I/O (Operation not permitted)
>>>>
>>>>  87 [   101.334] (EE) open /dev/fb0: Permission denied
>>>>
>>>>
>>>> What is strange the X logs  ( bad and Ok ) files essentially appear as if GNOME started !
>>>>
>>>>
>>>>
>>>>
>>>> <Xorg.0.log.bad><Xorg.0.log.Ok>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>>
>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> Here is my cmdline  -  I just tested 5.3.0 and it fails too  ( my last test was 5.3.8 and it failed also ) . 
>>>>>>
>>>>>> # cat /proc/cmdline 
>>>>>> BOOT_IMAGE=(hd0,msdos1)/vmlinuz-5.3.0+ root=/dev/mapper/ol_ca--dev55-root ro crashkernel=auto resume=/dev/mapper/ol_ca--dev55-swap rd.lvm.lv=ol_ca-dev55/root rd.lvm.lv=ol_ca-dev55/swap console=ttyS0,9600,8,n,1 drm.debug=0xff
>>>>>>
>>>>>> When you say “tip”. - Are you referring to a specific kernel  ?  I can build a  5.4.0.rc6  ;   The problem appears to have been introduced around 5.3 time frame. 
>>>>>
>>>>> The latest and greatest DRM code is in the drm-tip branch at
>>>>>
>>>>> git://anongit.freedesktop.org/drm/drm-tip
>>>>>
>>>>> If you build this version you should find
>>>>>
>>>>> /sys/kernel/debug/dri/0/vram-mm
>>>>>
>>>>> on the device. You have to build with debugfs enabled and
>>>>> maybe have to mount debugfs at /sys/kernel/debug.
>>>>>
>>>>>
>>>>>>
>>>>>>
>>>>>>>
>>>>>>> before and after switching to graphics mode. The file lists the
>>>>>>> allocated regions of the VRAM.
>>>>>>>
>>>>>>>>
>>>>>>>> This adapter is  Server Engines  Integrated Remote Video Acceleration Subsystem (RVAS)  and is used as remote console in iLO/DRAC environments.  
>>>>>>>>
>>>>>>>> I don’t see any specific errors in the gdm logs or message file other than this:
>>>>>>>
>>>>>>> You can boot with drm.debug=0xff on the kernel command line to enable
>>>>>>> more warnings.
>>>>>>>
>>>>>>>
>>>>>>> Could you please attach the output of lspci -v for the VGA adapter?
>>>>>>>
>>>>>>
>>>>>>
>>>>>> Here is the output from the current machine; The previous addresses were from another model using the same SE device:
>>>>>>
>>>>>>
>>>>>> Nov  7 04:42:50 ca-dev55 kernel: mgag200 0000:3d:00.0: remove_conflicting_pci_framebuffers: bar 0: 0xc5000000 -> 0xc5ffffff
>>>>>> Nov  7 04:42:50 ca-dev55 kernel: mgag200 0000:3d:00.0: remove_conflicting_pci_framebuffers: bar 1: 0xc6810000 -> 0xc6813fff
>>>>>> Nov  7 04:42:50 ca-dev55 kernel: mgag200 0000:3d:00.0: remove_conflicting_pci_framebuffers: bar 2: 0xc6000000 -> 0xc67fffff
>>>>>> Nov  7 04:42:50 ca-dev55 kernel: mgag200 0000:3d:00.0: vgaarb: deactivate vga console
>>>>>>
>>>>>>
>>>>>> lspci -s 3d:00.0 -vvv -k 
>>>>>> 3d:00.0 VGA compatible controller: Matrox Electronics Systems Ltd. MGA G200e [Pilot] ServerEngines (SEP1) (rev 05) (prog-if 00 [VGA controller])
>>>>>> 	Subsystem: Oracle/SUN Device 4852
>>>>>> 	Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr+ Stepping- SERR+ FastB2B- DisINTx-
>>>>>> 	Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
>>>>>> 	Latency: 0, Cache Line Size: 64 bytes
>>>>>> 	Interrupt: pin A routed to IRQ 16
>>>>>> 	NUMA node: 0
>>>>>> 	Region 0: Memory at c5000000 (32-bit, non-prefetchable) [size=16M]
>>>>>> 	Region 1: Memory at c6810000 (32-bit, non-prefetchable) [size=16K]
>>>>>> 	Region 2: Memory at c6000000 (32-bit, non-prefetchable) [size=8M]
>>>>>> 	Expansion ROM at 000c0000 [disabled] [size=128K]
>>>>>> 	Capabilities: [dc] Power Management version 2
>>>>>> 		Flags: PMEClk- DSI+ D1- D2- AuxCurrent=0mA PME(D0-,D1-,D2-,D3hot-,D3cold-)
>>>>>> 		Status: D0 NoSoftRst- PME-Enable- DSel=0 DScale=0 PME-
>>>>>> 	Capabilities: [e4] Express (v1) Legacy Endpoint, MSI 00
>>>>>> 		DevCap:	MaxPayload 256 bytes, PhantFunc 0, Latency L0s <64ns, L1 <1us
>>>>>> 			ExtTag- AttnBtn- AttnInd- PwrInd- RBE- FLReset-
>>>>>> 		DevCtl:	Report errors: Correctable+ Non-Fatal+ Fatal+ Unsupported-
>>>>>> 			RlxdOrd- ExtTag- PhantFunc- AuxPwr- NoSnoop-
>>>>>> 			MaxPayload 128 bytes, MaxReadReq 128 bytes
>>>>>> 		DevSta:	CorrErr+ UncorrErr- FatalErr- UnsuppReq+ AuxPwr- TransPend-
>>>>>> 		LnkCap:	Port #0, Speed 2.5GT/s, Width x1, ASPM L0s, Exit Latency L0s <64ns
>>>>>> 			ClockPM- Surprise- LLActRep- BwNot- ASPMOptComp-
>>>>>> 		LnkCtl:	ASPM Disabled; RCB 64 bytes Disabled- CommClk+
>>>>>> 			ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt-
>>>>>> 		LnkSta:	Speed 2.5GT/s, Width x1, TrErr- Train- SlotClk+ DLActive- BWMgmt- ABWMgmt-
>>>>>> 	Capabilities: [54] MSI: Enable- Count=1/1 Maskable- 64bit-
>>>>>> 		Address: 00000000  Data: 0000
>>>>>> 	Kernel driver in use: mgag200
>>>>>> 	Kernel modules: mgag200
>>>>>
>>>>> Looks all normal.
>>>>>
>>>>> Best regards
>>>>> Thomas
>>>>>
>>>
>>> ==============  Snip  ===========
>>>
>>>
>>> Hi Thomas 
>>> ,
>>> I hopefully narrowed down the breakage between these up-stream commits,  which is v5.2 and 5.3.0-rc1:   
>>>
>>>
>>> between :  0ecfebd2b524 2019-07-07 | Linux 5.2      to :   5f9e832c1370 2019-07-21 | Linus 5.3-rc1
>>>
>>>
>>> I started to bisect this range on by date, by day ,  based on the changes done in :
>>>
>>> drivers/gpu/drm/
>>>
>>> fec88ab0af97 2019-07-14 | Merge tag 'for-linus-hmm' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma  ;  works 
>>>
>>> Hopefully something in drivers/gpu/drm/ between the date range of 2019-07-14 to 2019-07-21 will surface tomorrow.
>>
>> Great, thanks for bisecting.
>>
>> Could you attach your kernel config file? I'd like to compare with my
>> config and try to reproduce the issue.
>>
>> Best regards
>> Thomas
> 
>   Hi.
> 
>   Here are config files generated after a “ make oldconfig “     that started with an original .config file from a master file  we use for 5.4.0.-rc4. :
> 
>      config.5.2.21 -  work with that flavor
>     config.5.3.   fails with 5.3 and later. 
> 
>   Do you have access to mgag200 style adapter ?  

I do.

I think I've been able to reproduce the issue. Buffers seem to remain in
video ram after they have been pinned there. I'll investigate next week.
I hope your bisecting session can point to the cause.

Best regards
Thomas

> 
> 
> 
> 
> 
> 

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer

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