SWMBO has one of those very small desktop PCs that's basically laptop
hardware in an old sandwich packet.

It's a Lenovo Thinkcentre M73 Tiny. A fairly vanilla Core i3 box with
an intel H81 chipset. It has VGA and DisplayPort outputs (there's an
option available for an HDMI or second DP output, but not fitted to her
PC).

She's just bought a second monitor. I wired it up to the DP connector
as her old monitor is on the VGA ... and the desktop comes up nicely on
the new monitor, but the old one complains of "No signal" and goes to
sleep. If I unplug the new monitor, the old one works as before.

Windows 10 offers to look for a second display, but says there isn't
one.

The Intel Ark pages for the H81 say that it can support two monitors
operating independently at once.

I thought the BIOS might have an option to enable a second monitor, but
it didn't. I updated the BIOS (which was quite old) and it still
doesn't.

I swapped the monitors round (they're the same model) and still the one
on VGA went to sleep if the DP one was connected.

Does this ring any bells with anyone? Is there anything else I should
have tried?

--
Cheers,
Daniel.

On 13/08/2022 18:49, Daniel James wrote:

> Does this ring any bells with anyone? Is there anything else I should
> have tried?
>

My memory of when multiple monitor support came out, was that the
motherboard/display adapter manual would list supported configurations.

A VGA only monitor sounds very old, does it support HDMI too?

On 13/08/2022 22:15, Pancho wrote:
> On 13/08/2022 18:49, Daniel James wrote:
>
>> Does this ring any bells with anyone? Is there anything else I should
>> have tried?
>>
>
> My memory of when multiple monitor support came out, was that the
> motherboard/display adapter manual would list supported configurations.
>
> A VGA only monitor sounds very old, does it support HDMI too?

more likely to support DVI ?

--
random signature text inserted here

In article <td948m$2tqr0$1@dont-email.me>, Pancho wrote:
> My memory of when multiple monitor support came out, was that the
> motherboard/display adapter manual would list supported configurations.

The PC was bought refurbished ... the manuals I've found online aren't
that specific about combinations of displays, but does say that two
monitors are supported.

> A VGA only monitor sounds very old, does it support HDMI too?

It's not that the monitors require VGA (they have VGA, DVI-D, HDMI, and
DP) but that the PC has one VGA and one DP port, so to use two monitors
one of them would have to be VGA.

As the PC is a "Tiny" model there's no room for any expansion card.
Lenovo did sell these with an additional HDMI port (there's a blanking
plate on the back of the case where this would go) but I don't know
whether it was ever sold as an upgrade - I certainly haven't been able to
find one.

If I can't get VGA+DP to work the only option left would seem to be a USB
display adaptor (or a new PC) but we'd rather not spend the money!

My question, really, was: The H81 chipset appears to support two
displays, so is the fact that it's not working here

a) A Lenovo hardware design limitation
b) A Lenovo firmware limitation
c) A Windows10/driver limitation

I don't think it's a hardware limitation, as I've seen discussion online
about getting a *third* display working (you can't, but two apparently
worked for them, under Windows 7)

As I said, I've already updated the BIOS to the latest (from 4th Jan this
year) ... so I don't think it's a firmware limitation.

I don't know much about Windows 10, though. I'm more of a Linux guy these
days. We appear to have the latest drivers (according to Device Manager)
but is there anything else I need to get dual-monitor support?

Thanks for your help.

--
Cheers,
Daniel.

On 14 Aug 2022 at 13:24:09 BST, "Daniel James" <daniel@me.invalid>
wrote:

> I don't know much about Windows 10, though. I'm more of a Linux guy these
> days. We appear to have the latest drivers (according to Device Manager)
> but is there anything else I need to get dual-monitor support?

There isn't, so I'd suspect (a) or (b). Have you had a dive through the
BIOS to see if there's a setting to allow dual? And updated the BIOS?

Cheers - Jaimie
--
"Don't drag me down to your level, meat."
-- Red Robot #C-63

In article <VA.00000da9.0019cc4d@me.invalid>, Daniel James wrote...
>
> In article <td948m$2tqr0$1@dont-email.me>, Pancho wrote:
> > My memory of when multiple monitor support came out, was that the
> > motherboard/display adapter manual would list supported configurations.
>
> The PC was bought refurbished ... the manuals I've found online aren't
> that specific about combinations of displays, but does say that two
> monitors are supported.
>
> > A VGA only monitor sounds very old, does it support HDMI too?
>
> It's not that the monitors require VGA (they have VGA, DVI-D, HDMI, and
> DP) but that the PC has one VGA and one DP port, so to use two monitors
> one of them would have to be VGA.
>
> As the PC is a "Tiny" model there's no room for any expansion card.
> Lenovo did sell these with an additional HDMI port (there's a blanking
> plate on the back of the case where this would go) but I don't know
> whether it was ever sold as an upgrade - I certainly haven't been able to
> find one.
>
> If I can't get VGA+DP to work the only option left would seem to be a USB
> display adaptor (or a new PC) but we'd rather not spend the money!
>
> My question, really, was: The H81 chipset appears to support two
> displays, so is the fact that it's not working here
>
> a) A Lenovo hardware design limitation
> b) A Lenovo firmware limitation
> c) A Windows10/driver limitation
>
> I don't think it's a hardware limitation, as I've seen discussion online
> about getting a *third* display working (you can't, but two apparently
> worked for them, under Windows 7)
>
> As I said, I've already updated the BIOS to the latest (from 4th Jan this
> year) ... so I don't think it's a firmware limitation.
>
> I don't know much about Windows 10, though. I'm more of a Linux guy these
> days. We appear to have the latest drivers (according to Device Manager)
> but is there anything else I need to get dual-monitor support?
>
> Thanks for your help.

Risking getting shot down here, as this isn't a subject I know comprehensively,
but I wonder if there's anything in these articles which might help you spot
the problem?

https://bit.ly/3pghs5x
https://www.computerhope.com/issues/ch000801.htm

In particular, note the existence of a Function key on most laptops which
controls the display when a secondary display is connected (allows you to blank
and enable a projector, for example). Google (images) "laptop display function
key" for examples of what this looks like.

How much this functionality overlaps with the Winkey+P control I couldn't say!

--

Phil, London

On 14/08/2022 13:24, Daniel James wrote:

>
> It's not that the monitors require VGA (they have VGA, DVI-D, HDMI, and
> DP) but that the PC has one VGA and one DP port, so to use two monitors
> one of them would have to be VGA.
>

AIUI, you can daisy-chain DP monitors. You can connect multiple monitors
from a single DP port/cable.

On 14/08/2022 01:27, Abandoned_Trolley wrote:
> On 13/08/2022 22:15, Pancho wrote:
>> On 13/08/2022 18:49, Daniel James wrote:
>>
>>> Does this ring any bells with anyone? Is there anything else I should
>>> have tried?
>>>
>>
>> My memory of when multiple monitor support came out, was that the
>> motherboard/display adapter manual would list supported configurations.
>>
>> A VGA only monitor sounds very old, does it support HDMI too?
>
>
> more likely to support DVI ?
>
Yes, indeed, how quickly we forget.

On 13/08/2022 18:49, Daniel James wrote:
> Thinkcentre M73

https://support.lenovo.com/gb/en/solutions/ht062228?tabName=Solutions

On 14/08/2022 15:09, Pancho wrote:
> On 14/08/2022 13:24, Daniel James wrote:
>
>>
>> It's not that the monitors require VGA (they have VGA, DVI-D, HDMI, and
>> DP) but that the PC has one VGA and one DP port, so to use two monitors
>> one of them would have to be VGA.
>>
>
> AIUI, you can daisy-chain DP monitors. You can connect multiple monitors
> from a single DP port/cable.
>
Actually, Ignore that. You need display port 1.2, which I don't think
the H81 is.

Daniel James <daniel@me.invalid> wrote:
> SWMBO has one of those very small desktop PCs that's basically laptop
> hardware in an old sandwich packet.
>
> It's a Lenovo Thinkcentre M73 Tiny. A fairly vanilla Core i3 box with
> an intel H81 chipset. It has VGA and DisplayPort outputs (there's an
> option available for an HDMI or second DP output, but not fitted to her
> PC).
>
> She's just bought a second monitor. I wired it up to the DP connector
> as her old monitor is on the VGA ... and the desktop comes up nicely on
> the new monitor, but the old one complains of "No signal" and goes to
> sleep. If I unplug the new monitor, the old one works as before.
>
> Windows 10 offers to look for a second display, but says there isn't
> one.
>
> The Intel Ark pages for the H81 say that it can support two monitors
> operating independently at once.
>
> I thought the BIOS might have an option to enable a second monitor, but
> it didn't. I updated the BIOS (which was quite old) and it still
> doesn't.
>
> I swapped the monitors round (they're the same model) and still the one
> on VGA went to sleep if the DP one was connected.
>
> Does this ring any bells with anyone? Is there anything else I should
> have tried?

What's the resolution of the monitor in DP mode? It's possible there's a
bandwidth limitation and you can only run two if they're at the same,
lower, resolution. Probably something like 1280x1024. Or at least start
with that and if it works keep increasing the resolution until it stops.

In article <jls9inFibggU1@mid.individual.net>, Jaimie Vandenbergh
wrote:
> Have you had a dive through the
> BIOS to see if there's a setting to allow dual? And updated the BIOS?

I have, and I have.

I found a support article on the Lenovo website that shows a
"Multi-Monitor Support" entry in the BIOS that isn't present in the
BIOS here. I updated the BIOS to the latest and it still isn't present.

https://pcsupport.lenovo.com/gb/en/solutions/ht062228?tabName=Solutions

I can only assume that the BIOS for one of the other models of
ThinkCentre machine covered by that article has such an entry.

*However* my reply to Pancho yesterday made me think this was probably
a Windows issue ... so I booted the PC from a Linux Live-USB stick and
both monitors immediately sprang into life.

My question is now:

Why is Windows 10 making the VGA monitor go to sleep when it detects
that there is a DisplayPort monitor attached?

(I really don't want to, but I'm starting to think I should take the
Win10 SSD out and put back the old Win7 HDD to see whether it works
there.)

--
Cheers,
Daniel.

In article <MPG.3d6303e68c28891a989a13@news.eternal-september.org>,
Philip Herlihy wrote:
> Risking getting shot down here, as this isn't a subject I know
> comprehensively, but ...

Thanks, Phil. I'm pretty sure you know modern Windows systems better
than I do.

> I wonder if there's anything in these articles which might help you
> spot the problem?
>
> https://bit.ly/3pghs5x
> https://www.computerhope.com/issues/ch000801.htm

The first of those I'd seen already -- the problem is that something
(Windows, I now suspect) seems to be disabling the VGA output from the
PC so the monitor goes into standby. The "Detect" button mentioned in
that article just tells me that there aren't any other monitors, so the
dual-monitor option isn't enabled.

The second is interesting ... but I know how to recognize the ports,
and as the second monitor isn't being recognized Win+P doesn't help.

The Question (As I said to Jaimie) is that Windows seems to be
recognizing the DP monitor and then disabling the VGA one. I'm now
pretty sure it must be Windows that's doing this as both monitors work
under Linux.

> In particular, note the existence of a Function key on most laptops
> which controls the display when a secondary display is connected
> (allows you to blank and enable a projector, for example). Google
> (images) "laptop display function key" for examples of what this
> looks like.

Yes, I know about that -- I often use an external monitor with my
laptop. The machine I'm trying to get working with two monitors isn't a
laptop, though, and so doesn't have a "Fn" key like laptops do ... and
I'm not sure whether I could enter an equivalent code from a normal
keyboard ... especially as the system isn't recognizing the monitor at
all anyway. This may be something I should look further into, though,
so thanks again.

--
Cheers,
Daniel.

In article <tdct49$3hkce$1@dont-email.me>, Chris wrote:
> What's the resolution of the monitor in DP mode? It's possible
> there's a bandwidth limitation and you can only run two if they're
> at the same,

Good thought ... but these are 1920x1200 monitors which is about the
limit for VGA but no great shakes for DP.

They run fine together at that resolution under Linux, so this looks
like a Windows problem.

--
Cheers,
Daniel.

Daniel James <daniel@me.invalid> wrote:
> Why is Windows 10 making the VGA monitor go to sleep when it detects
> that there is a DisplayPort monitor attached?

Just a thought, but I wonder if you have appropriate drivers installed? I
think Windows will install to begin with with generic drivers (it used to be
a SVGA card with an 800x600 display but I think it's better these days,
maybe FHD) and then Windows Update will pull in all the drivers for the
hardware that you have. I did a couple of Windows 10 (Insider) installs
lately and that's what it did - it did cause the display to resize halfway
through, as presumably that was it detecting the display that was attached
rather the default resolution.

Have you checked in Windows update to ensure all the Intel HD graphics
drivers are installed and up to date? There may also be drivers needed for
the Displayport controller - not sure what they would be called. Device
Manager may tell you if there's something missing - have a poke through all
the categories and see if anything is complaining.

I think this machine predates Windows 10 so it may not have shipped with
Windows 10 drivers. I think the Intel HD graphics should be fine, but it's
possible Lenovo used some Displayport chip that doesn't have Windows 10
drivers. Although I'm not seeing anything like that on the driver download
page.

(I've had that once with a touchscreen - got it to work once under 10 by
force loading the Win7 drivers, but the next Win10 update killed it)

Theo

Daniel James <daniel@me.invalid> wrote:
> In article <tdct49$3hkce$1@dont-email.me>, Chris wrote:
>> What's the resolution of the monitor in DP mode? It's possible
>> there's a bandwidth limitation and you can only run two if they're
>> at the same,
>
> Good thought ... but these are 1920x1200 monitors which is about the
> limit for VGA but no great shakes for DP.
>
> They run fine together at that resolution under Linux, so this looks
> like a Windows problem.

More likely a driver problem. Either you don't have an optimised driver for
your machine and/or your set up isn't supported by Win10.

I would still try the resolution just to be sure.

On 15 Aug 2022 at 20:06:37 BST, "Theo"
<theom+news@chiark.greenend.org.uk> wrote:

> Daniel James <daniel@me.invalid> wrote:
>> Why is Windows 10 making the VGA monitor go to sleep when it detects
>> that there is a DisplayPort monitor attached?
>
> Just a thought, but I wonder if you have appropriate drivers installed?

Mm. I hadn't expected it to be a Windows side issue, but those Intel
drivers are awful so it certainly could be. And the OEM repackages of
them are always even worse, and usually years out of date.

https://www.intel.com/content/www/us/en/download/19344/intel-graphics-windows-dch-drivers.html
- see if the chipset is in there.

Might need to run DDU to unlock the oem-drivers-only limitation too.
https://www.wagnardsoft.com/

Cheers - Jaimie

--
The Daily Mail should be forced to print the words
'The Paper That Supported Hitler' on its masthead,
just so that there is something that's true on the
front page every day. -- Mark Thomas

On 8/13/2022 12:49 PM, Daniel James wrote:
> SWMBO has one of those very small desktop PCs that's basically laptop
> hardware in an old sandwich packet.
>
> It's a Lenovo Thinkcentre M73 Tiny. A fairly vanilla Core i3 box with
> an intel H81 chipset. It has VGA and DisplayPort outputs (there's an
> option available for an HDMI or second DP output, but not fitted to her
> PC).
>
> She's just bought a second monitor. I wired it up to the DP connector
> as her old monitor is on the VGA ... and the desktop comes up nicely on
> the new monitor, but the old one complains of "No signal" and goes to
> sleep. If I unplug the new monitor, the old one works as before.
>
> Windows 10 offers to look for a second display, but says there isn't
> one.
>
> The Intel Ark pages for the H81 say that it can support two monitors
> operating independently at once.
>
> I thought the BIOS might have an option to enable a second monitor, but
> it didn't. I updated the BIOS (which was quite old) and it still
> doesn't.
>
> I swapped the monitors round (they're the same model) and still the one
> on VGA went to sleep if the DP one was connected.
>
> Does this ring any bells with anyone? Is there anything else I should
> have tried?
>
Try the two key combination "Windows key" and letter "P" and see if that
breaks through the problem.
If it does try the Extend choice and see if both monitors start working
at the same time.

In article <jlvq62F46suU1@mid.individual.net>, Jaimie Vandenbergh
wrote:
> Mm. I hadn't expected it to be a Windows side issue, but those Intel
> drivers are awful so it certainly could be. And the OEM repackages of
> them are always even worse, and usually years out of date.
>
>
https://www.intel.com/content/www/us/en/download/19344/intel-graphics-w
indows-dch-drivers.html
> - see if the chipset is in there.

Ah! Thank you Jaimie!

No, the chipset isn't there -- this is an 13-4130T with the H8 chipset
so I needed an older driver bundle, but the approach was spot on.

I had looked at the display drivers in Device Manager (Microsoft Basic
Display, or something like that) and had clicked "Update" only to be
told that I already had the best driver for the hardware and it was
up-to-date ... so although I'm always cynical of messages of that sort
I knew no better than to believe it. What lies Microsoft tell, eh?

All working fine, now (once I worked out how to get the two screens in
the right order).

Thanks to everyone who gave this some thought.

--
Cheers,
Daniel.

In article <tdesi8$3s0tp$1@dont-email.me>, GlowingBlueMist wrote:
> Try the two key combination "Windows key" and letter "P" and see
> if that breaks through the problem.

No, that just told me I only had one monitor. It was a driver issue and
Jaimie pointed me in the direction of a solution. All working nicely,
now; but thanks.

--
Cheers,
Daniel.

On 16 Aug 2022 at 16:09:36 BST, "Daniel James" <daniel@me.invalid>
wrote:

> In article <tdesi8$3s0tp$1@dont-email.me>, GlowingBlueMist wrote:
>> Try the two key combination "Windows key" and letter "P" and see
>> if that breaks through the problem.
>
> No, that just told me I only had one monitor. It was a driver issue and
> Jaimie pointed me in the direction of a solution. All working nicely,
> now; but thanks.

Hurray! Thanks Theo for pointing out the flaw in my expectations :D

Rare of me to *not* be pessimistic about Windows, too.

Cheers - Jaimie
--
"Some people think that noise abatement should be a higher
priority for ATC. I say safety is noise abatement. You have no
idea how much noise it makes to have a 737 fall out of the sky
after an accident."
-- anonymous air traffic controller