Bios bug: Latitude 7440

Hello Dell team,

with my E7440, I have also the same problems (Win 8.1).

After BIOS upgrate ver. 15, I have CPU speed issues every day. Only restarting can solve my problem. But I havent time for restarting my laptop 10 times per day.

Is there some workaround for fixing CPU speed without restart? I tried to hibernate and after wake up the CPU frequency was ok. But sometimes the laptop wake up and no application is running. Hibernate doesnt work everytime.

Cheers

Hi,

I have E5540, which also had keyboard problems. After updating to latest A12 BIOS keyboard problems mostly resolved, but now I am also experience minimum CPU frequency after resuming from sleep state on battery. Funny thing is that I did not had CPU frequency problem before, and it was introduced in A12, which states "Fixed CPU may stay at low speed after resume from standby" in it's changelog!

I have this as well, had it with earlier bios versions and still have it at an even higher rate of occurrence on Bios V15.

This laptop has been a nightmare from day 1 and I'm starting to get really fed up with it. 3 new batteries, motherboard that didn't recognize the power adapter wattage correctly twice and now this... :(

Two more months of this *** with nothing from Dell either in the forums, bios updates or from the support... Completely useless.

Time to switch to Apple?

There are  downsides as well:  the hardware costs at least twice as much, and Apple hardware essentially becomes competely unsupported after two more OS cycles (i.e., three years).  The last one is even more significant:  everything including the SSD on many models is permanently mounted inside with adhesive or solder.  Translation:  since any failure requires an expensive logic board replacement (at 3X or more what Dell charges), get 3-year AppleCare to carry the system until it's obsolete and ready for recycling.

You are only right about with a Mac you cannot change anything but... It costs at least twice? You kidding? The same business laptop with Apple was cheaper than my E7440 with 8 GB of RAM, i7 and 256 GB SSD.

Three years of OS support? OS X El Capitan supports Macs from 2008, please get more informed next time.

Apple Care + is cheaper than Dell support. Anyway, this is a business laptop, not for a average customer and MacBook Pro is neither. This is my experience. No more Dell.

My reference was to hardware support by OS cycle - not the OS itself.  Good luck getting repair support from Apple once three years are up.

There's nothing wrong with Apple's systems - the hardware in most cases is so closely similar to what's inside a PC (the manufacturers are, after all, the same - Apple's systems are built by the same contractors that make systems for Dell, HP, Lenovo, etc) -- and if you're expecting perfection, just ask anyone who's seen a Mac destroyed by a swollen battery or had a video chip fail, etc.   It does happen - and with about the same frequency as it does with Dell.

You DO get better support than with any PC vendor - yes.   Better hardware though?  Nope - it's the same, as is the frequency with which problems arise.

Has there been any update / response from Dell on this issue?

I have the same problem, and it is really frustrating.

I have the same CPU speed problem when waking from sleep with my Latitude E5540, but only since I updated to bios A12. (I also updated to Windows 10 but I don't think it's related to that update?)

Strange thing is that when I put the laptop to sleep by closing the lid, and I then open the lid, the problem occurs; but when I press the power button to put the laptop to sleep (and even close the lid), the problem doesn't occur when I wake the machine from sleep ...

Very annoying.

Nope, no news from Dell.

For linux users suffering from CPU frequencies lower that what should be the minimum available for their processor (for 4th gen, typically less than 800 MHz, and typically about 600 MHz), for 5th gen less than 500MHz) I am looking for additional confirming evidence that the root issue is that Clock Modulation is enabled. Method of test:

1.) (needed once per boot) sudo modprobe msr
2.) before any suspend: sudo rdmsr -a 0x19a
3.) after a suspend that results in the low CPU frequencies:
 sudo rdmsr -a 0x19a
4.) If the result from step 3 is that bit 4 is 1, then:
 sudo wrmsr -a 0x19a 0x0
and check it:
 sudo rdmsr -a 0x19a
5.) Are the CPU frequencies O.K. now?

Depending on your linux distribution, a recent version of  msr-tools
might be requiredto provide wrmsr and rdmsr.

For anybody from Dell that sees this: Can you confirm or deny that
you use Clock Modulation in your BIOS when you resume from
suspend on battery?

Note 1: The current version of the (linux) intel_pstate CPU frequency
scaling driver is not compatible with any use of Clock Modulation,
resulting in driving the target pstate to minimum, regardless of load.
What does that mean? Most typically, the Clock Modulation is 75%,
and so you end up stuck at around 600 MHz. There will still some
variation in CPU frequency, done by the processor itself within the range
of pstate 8.

Note 2: Myself, I do not suffer from this issue. I'm just attempting to get to
the root issue of all the complaints about CPU frequency stuck below what
should be the minimum for the processor.

I am experiencing CPU frequencies lower that what should be the minimum permanently, not only after suspend. I followed your instructions immediately after boot and login.

• Dell XPS13 (9343)
• BIOS A05
• BIOS: Intel SpeedStep, Intel TurboBoost enabled
• Ubuntu 15.04 (installed from scratch)

xx@yy:~$ lscpu
Architecture:          x86_64
CPU op-mode(s):        32-bit, 64-bit
Byte Order:            Little Endian
CPU(s):                4
On-line CPU(s) list:   0-3
Thread(s) per core:    2
Core(s) per socket:    2
Socket(s):             1
NUMA node(s):          1
Vendor ID:             GenuineIntel
CPU family:            6
Model:                 61
Model name:            Intel(R) Core(TM) i5-5200U CPU @ 2.20GHz
Stepping:              4
CPU MHz:               499.984
CPU max MHz:           2700,0000
CPU min MHz:           500,0000
BogoMIPS:              4389.97
Virtualization:        VT-x
L1d cache:             32K
L1i cache:             32K
L2 cache:              256K
L3 cache:              3072K
NUMA node0 CPU(s):     0-3
xx@yy:~$ sudo modprobe msr
[sudo] password for xx:
xx@yy:~$ sudo rdmsr -a 0x19a
e
e
e
e
xx@yy:~$ sudo wrmsr -a 0x19a 0x0
xx@yyi:~$ sudo rdmsr -a 0x19a
0
0
0
0

After this I put some load on the processer by running a simple shell-script and starting programs like vmware player, libre office wirter and in parallel greped repeatedly for the CPU-frequency:

xx@yyi:~$ lscpu |grep MHz
CPU MHz:               499.984
CPU max MHz:           2700,0000
CPU min MHz:           500,0000
xx@yy:~$ lscpu |grep MHz

... the output never changed.

P.S.: cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_driver
intel_pstate

I did several tests, the CPU-frequency seems to be frozen at 499,984 MHz. Only once during my tests I experienced a slight increase to a maximum of something like 501 MHz, however I am not able to reproduce this.

I also disabled SpeedStep in BIOS, expecting the frequency to be 2.200 MHz constantly, but it remained 499,984.

Thanks for all your effort and support!

@n13260: Your situation is different. The minimum pstate for your processor is 5 and so 500 MHZ without Clock Modulation is O.K. I can see that I need to edit my post, and bit 4 of the register indicates if Clock Modulation is enabled or not, and in your case it wasn't.

Often (not always), CPU frequencies stuck at minimum are because the BIOS is limiting the frequency . You can check via:

cat /sys/devices/system/cpu/cpu*/cpufreq/bios_limit

Although that file might not be there.  See also.

I had a similar problem that got even worse when using the latest bios.

But sometimes I got as low as 100 MHz which is way below the minimum speed.

Dell came out and replaced the motherboard and CPU, I haven't had the problem since then.