Forums

Shady Dell laptop practices

Started by bitrex January 8, 2018
On some of the inexpensive Dell laptops they implement a 
hardware-lockout system intended to prevent you from using aftermarket 
charger bricks to charge the battery. The way they do this is there's a 
chip in the Dell charger that contains a unique identifier which a chip 
on the laptop mobo requests from it on startup over a one-wire interface.

If on boot the BIOS can't confirm that the lockout chip on the mobo has 
asserted the "OEM OK" pin or whatever the BIOS then proceeds to muck 
around with the processor MSRs (model-specific registers) and alter 
their state, specifically the BD_PROCHOT register, which is a flag bit 
that is usually controlled by the motherboard temperature sensor.

Flipping that makes the processor think the motherboard is overheating, 
which disables battery charging and has the additional nice "feature" of 
throttling the processor down to around 400MHz from 2.8 GHz or whatever. 
So not only can you not charge the battery you can't really use the 
laptop on an aftermarket brick even when plugged into the wall. Also 
there's then no way to tell if the laptop mobo is _actually_ overheating 
in that state.

Good news is that the MSRs are accessible via software, so it's not hard 
to write a script that runs after the OS start to flip the bit back, and 
everything is back to normal.
On 08/01/2018 15:03, bitrex wrote:
> On some of the inexpensive Dell laptops they implement a > hardware-lockout system intended to prevent you from using aftermarket > charger bricks to charge the battery. The way they do this is there's a > chip in the Dell charger that contains a unique identifier which a chip > on the laptop mobo requests from it on startup over a one-wire interface. > > If on boot the BIOS can't confirm that the lockout chip on the mobo has > asserted the "OEM OK" pin or whatever the BIOS then proceeds to muck > around with the processor MSRs (model-specific registers) and alter > their state, specifically the BD_PROCHOT register, which is a flag bit > that is usually controlled by the motherboard temperature sensor. > > Flipping that makes the processor think the motherboard is overheating, > which disables battery charging and has the additional nice "feature" of > throttling the processor down to around 400MHz from 2.8 GHz or whatever. > So not only can you not charge the battery you can't really use the > laptop on an aftermarket brick even when plugged into the wall. Also > there's then no way to tell if the laptop mobo is _actually_ overheating > in that state. > > Good news is that the MSRs are accessible via software, so it's not hard > to write a script that runs after the OS start to flip the bit back, and > everything is back to normal.
My Dell laptop charger used a Dallas-Maxim DS2401 serial number 1-wire device. I didn't know if Dell bought a block of pre-assigned ID numbers of whether any 1-wire ID would work. When the Dell charger died I transplanted the TO-92 sized (easy to handle) DS2401 from out the original into a kludged splice in the cable of the replacement charger - which claims to have enough current capacity. The laptop is happy. piglet
On Monday, January 8, 2018 at 10:04:00 AM UTC-5, bitrex wrote:
> On some of the inexpensive Dell laptops they implement a > hardware-lockout system intended to prevent you from using aftermarket > charger bricks to charge the battery. The way they do this is there's a > chip in the Dell charger that contains a unique identifier which a chip > on the laptop mobo requests from it on startup over a one-wire interface. > > If on boot the BIOS can't confirm that the lockout chip on the mobo has > asserted the "OEM OK" pin or whatever the BIOS then proceeds to muck > around with the processor MSRs (model-specific registers) and alter > their state, specifically the BD_PROCHOT register, which is a flag bit > that is usually controlled by the motherboard temperature sensor. > > Flipping that makes the processor think the motherboard is overheating, > which disables battery charging and has the additional nice "feature" of > throttling the processor down to around 400MHz from 2.8 GHz or whatever. > So not only can you not charge the battery you can't really use the > laptop on an aftermarket brick even when plugged into the wall. Also > there's then no way to tell if the laptop mobo is _actually_ overheating > in that state. > > Good news is that the MSRs are accessible via software, so it's not hard > to write a script that runs after the OS start to flip the bit back, and > everything is back to normal.
They're trying to avoid the bad publicity of a laptop spontaneously combusting because some jerk charged it with a knockoff charger.
On 01/08/2018 02:03 PM, bloggs.fredbloggs.fred@gmail.com wrote:
> On Monday, January 8, 2018 at 10:04:00 AM UTC-5, bitrex wrote: >> On some of the inexpensive Dell laptops they implement a >> hardware-lockout system intended to prevent you from using aftermarket >> charger bricks to charge the battery. The way they do this is there's a >> chip in the Dell charger that contains a unique identifier which a chip >> on the laptop mobo requests from it on startup over a one-wire interface. >> >> If on boot the BIOS can't confirm that the lockout chip on the mobo has >> asserted the "OEM OK" pin or whatever the BIOS then proceeds to muck >> around with the processor MSRs (model-specific registers) and alter >> their state, specifically the BD_PROCHOT register, which is a flag bit >> that is usually controlled by the motherboard temperature sensor. >> >> Flipping that makes the processor think the motherboard is overheating, >> which disables battery charging and has the additional nice "feature" of >> throttling the processor down to around 400MHz from 2.8 GHz or whatever. >> So not only can you not charge the battery you can't really use the >> laptop on an aftermarket brick even when plugged into the wall. Also >> there's then no way to tell if the laptop mobo is _actually_ overheating >> in that state. >> >> Good news is that the MSRs are accessible via software, so it's not hard >> to write a script that runs after the OS start to flip the bit back, and >> everything is back to normal. > > They're trying to avoid the bad publicity of a laptop spontaneously combusting because some jerk charged it with a knockoff charger. >
It's superfluous from a battery-charging safety perspective; the laptop's charge management system/IC is perfectly capable of handling an under-spec aftermarket charger being plugged in. It'll have undervoltage lock-out and likely can sense the brick's output impedance well enough to crowbar the charging current to a safe value if the input rail starts sagging. It won't be the laptop itself that catches fire, in any case. If it's really an important safety/PR-protection device it raises the question of why it's implemented on some models and not on others.
On 1/8/2018 7:03 AM, bitrex wrote:
> On some of the inexpensive Dell laptops they implement a > hardware-lockout system intended to prevent you from using aftermarket > charger bricks to charge the battery. The way they do this is there's a > chip in the Dell charger that contains a unique identifier which a chip > on the laptop mobo requests from it on startup over a one-wire interface. > > If on boot the BIOS can't confirm that the lockout chip on the mobo has > asserted the "OEM OK" pin or whatever the BIOS then proceeds to muck > around with the processor MSRs (model-specific registers) and alter > their state, specifically the BD_PROCHOT register, which is a flag bit > that is usually controlled by the motherboard temperature sensor. > > Flipping that makes the processor think the motherboard is overheating, > which disables battery charging and has the additional nice "feature" of > throttling the processor down to around 400MHz from 2.8 GHz or whatever. > So not only can you not charge the battery you can't really use the > laptop on an aftermarket brick even when plugged into the wall. Also > there's then no way to tell if the laptop mobo is _actually_ overheating > in that state. > > Good news is that the MSRs are accessible via software, so it's not hard > to write a script that runs after the OS start to flip the bit back, and > everything is back to normal.
got a link to such a script?
On 01/08/2018 03:56 PM, mike wrote:
> On 1/8/2018 7:03 AM, bitrex wrote: >> On some of the inexpensive Dell laptops they implement a >> hardware-lockout system intended to prevent you from using aftermarket >> charger bricks to charge the battery. The way they do this is there's a >> chip in the Dell charger that contains a unique identifier which a chip >> on the laptop mobo requests from it on startup over a one-wire interface. >> >> If on boot the BIOS can't confirm that the lockout chip on the mobo has >> asserted the "OEM OK" pin or whatever the BIOS then proceeds to muck >> around with the processor MSRs (model-specific registers) and alter >> their state, specifically the BD_PROCHOT register, which is a flag bit >> that is usually controlled by the motherboard temperature sensor. >> >> Flipping that makes the processor think the motherboard is overheating, >> which disables battery charging and has the additional nice "feature" of >> throttling the processor down to around 400MHz from 2.8 GHz or whatever. >> So not only can you not charge the battery you can't really use the >> laptop on an aftermarket brick even when plugged into the wall. Also >> there's then no way to tell if the laptop mobo is _actually_ overheating >> in that state. >> >> Good news is that the MSRs are accessible via software, so it's not hard >> to write a script that runs after the OS start to flip the bit back, and >> everything is back to normal. > got a link to such a script?
This isn't a shell script but can be saved as a .c file and compiled with gcc so it's in theory OS-independent (though I believe "asprintf" may be Linux-only so that line might have to be changed). Requires superuser/root/administrator privileges to execute successfully https://pastebin.com/yqa9Sz9w On the Window's side there's also a tool called "ThrottleStop" which has a radio button that can be clicked to toggle the bit manually.
On Mon, 8 Jan 2018 10:03:50 -0500, bitrex <bitrex@de.lete.earthlink.net>
wrote:

>On some of the inexpensive Dell laptops they implement a >hardware-lockout system intended to prevent you from using aftermarket >charger bricks to charge the battery. The way they do this is there's a >chip in the Dell charger that contains a unique identifier which a chip >on the laptop mobo requests from it on startup over a one-wire interface. > >If on boot the BIOS can't confirm that the lockout chip on the mobo has >asserted the "OEM OK" pin or whatever the BIOS then proceeds to muck >around with the processor MSRs (model-specific registers) and alter >their state, specifically the BD_PROCHOT register, which is a flag bit >that is usually controlled by the motherboard temperature sensor. > >Flipping that makes the processor think the motherboard is overheating, >which disables battery charging and has the additional nice "feature" of >throttling the processor down to around 400MHz from 2.8 GHz or whatever. >So not only can you not charge the battery you can't really use the >laptop on an aftermarket brick even when plugged into the wall. Also >there's then no way to tell if the laptop mobo is _actually_ overheating >in that state. > >Good news is that the MSRs are accessible via software, so it's not hard >to write a script that runs after the OS start to flip the bit back, and >everything is back to normal.
I woundn't own a Dell if it was free. They are the worst brand sold. They use parts made only for their systems. Even their case fans are made just for Dell, and they cost a fortune. I have my preferred brands, even though I build my own desktop machines, but Dell is not even on my list. I'll leave them in the store so someone else can waste their money on them and then dispose of them. Dell is Garbage !!!
On 01/08/2018 05:07 PM, oldschool@tubes.com wrote:
> On Mon, 8 Jan 2018 10:03:50 -0500, bitrex <bitrex@de.lete.earthlink.net> > wrote: > >> On some of the inexpensive Dell laptops they implement a >> hardware-lockout system intended to prevent you from using aftermarket >> charger bricks to charge the battery. The way they do this is there's a >> chip in the Dell charger that contains a unique identifier which a chip >> on the laptop mobo requests from it on startup over a one-wire interface. >> >> If on boot the BIOS can't confirm that the lockout chip on the mobo has >> asserted the "OEM OK" pin or whatever the BIOS then proceeds to muck >> around with the processor MSRs (model-specific registers) and alter >> their state, specifically the BD_PROCHOT register, which is a flag bit >> that is usually controlled by the motherboard temperature sensor. >> >> Flipping that makes the processor think the motherboard is overheating, >> which disables battery charging and has the additional nice "feature" of >> throttling the processor down to around 400MHz from 2.8 GHz or whatever. >> So not only can you not charge the battery you can't really use the >> laptop on an aftermarket brick even when plugged into the wall. Also >> there's then no way to tell if the laptop mobo is _actually_ overheating >> in that state. >> >> Good news is that the MSRs are accessible via software, so it's not hard >> to write a script that runs after the OS start to flip the bit back, and >> everything is back to normal. > > I woundn't own a Dell if it was free. They are the worst brand sold. > They use parts made only for their systems. Even their case fans are > made just for Dell, and they cost a fortune. I have my preferred brands, > even though I build my own desktop machines, but Dell is not even on my > list. I'll leave them in the store so someone else can waste their money > on them and then dispose of them. > > Dell is Garbage !!! > >
They were pretty solid in the 1990s, but I think there's a good reason they're not publicly-traded anymore.
On Monday, January 8, 2018 at 2:18:36 PM UTC-5, bitrex wrote:
> On 01/08/2018 02:03 PM, bloggs.fredbloggs.fred@gmail.com wrote: > > On Monday, January 8, 2018 at 10:04:00 AM UTC-5, bitrex wrote: > >> On some of the inexpensive Dell laptops they implement a > >> hardware-lockout system intended to prevent you from using aftermarket > >> charger bricks to charge the battery. The way they do this is there's a > >> chip in the Dell charger that contains a unique identifier which a chip > >> on the laptop mobo requests from it on startup over a one-wire interface. > >> > >> If on boot the BIOS can't confirm that the lockout chip on the mobo has > >> asserted the "OEM OK" pin or whatever the BIOS then proceeds to muck > >> around with the processor MSRs (model-specific registers) and alter > >> their state, specifically the BD_PROCHOT register, which is a flag bit > >> that is usually controlled by the motherboard temperature sensor. > >> > >> Flipping that makes the processor think the motherboard is overheating, > >> which disables battery charging and has the additional nice "feature" of > >> throttling the processor down to around 400MHz from 2.8 GHz or whatever. > >> So not only can you not charge the battery you can't really use the > >> laptop on an aftermarket brick even when plugged into the wall. Also > >> there's then no way to tell if the laptop mobo is _actually_ overheating > >> in that state. > >> > >> Good news is that the MSRs are accessible via software, so it's not hard > >> to write a script that runs after the OS start to flip the bit back, and > >> everything is back to normal. > > > > They're trying to avoid the bad publicity of a laptop spontaneously combusting because some jerk charged it with a knockoff charger. > > > > It's superfluous from a battery-charging safety perspective; the > laptop's charge management system/IC is perfectly capable of handling an > under-spec aftermarket charger being plugged in. It'll have undervoltage > lock-out and likely can sense the brick's output impedance well enough > to crowbar the charging current to a safe value if the input rail starts > sagging. It won't be the laptop itself that catches fire, in any case. > > If it's really an important safety/PR-protection device it raises the > question of why it's implemented on some models and not on others.
They may be doing some other stuff, you don't know.
oldschool@tubes.com wrote:


> I woundn't own a Dell if it was free. They are the worst brand sold. > They use parts made only for their systems. Even their case fans are > made just for Dell, and they cost a fortune. I have my preferred brands, > even though I build my own desktop machines, but Dell is not even on my > list. I'll leave them in the store so someone else can waste their money > on them and then dispose of them. > > Dell is Garbage !!!
I love Dells! I have found the commercial-grade models to be VERY good. I have had several Dell destop (Optiplex) machines run over 12 years in 24/7 operation. Yes, a lot of stuff in them is special, for instance the fans are made to be extra low-noise. Who cares, as you can put new bearings in them if they get noisy, or buy replacements on eBay. I have also had really good luck with their laptops, but again, there are some really great models and some that are a bit mediocre. I buy all my Dell boxes used for, usually, under $100 delivered. I did just have a motherboard go bad. First, it was bad capacitors, but then it just got sick. Possibly it is a bad capacitor with no visible signs. I only replaced the obvious ones. Jon