Skylake Bug

[fadsarmy]

Hi. Does this mean the actual hardware (cpu) is defective or flawed?

[kalniel]

Hi. Does this mean the actual hardware (cpu) is defective or flawed?

No way to know.

[fadsarmy]

I take it new batches will be bug free?

[kalniel]

I take it new batches will be bug free?

Even current batches are fixed in software I believe already.

[fadsarmy]

Even current batches are fixed in software I believe already.

That's not really a fix. You can't reprogram a cpu. It's a patch or whatever you want to call it. I meant will new batches require a bios update.

[MrJim]

That's not really a fix. You can't reprogram a cpu. It's a patch or whatever you want to call it. I meant will new batches require a bios update.

As I understand it, BIOS updates will include microcode fixes for the bug...

[kalniel]

That's not really a fix. You can't reprogram a cpu. It's a patch or whatever you want to call it. I meant will new batches require a bios update.

What's the difference between a fix and a patch? I expect all BIOSes will have the fix already now, unless you happen to buy from very old stock.

I grinned at the reprogramming a CPU comment

[fadsarmy]

The cpu is flawed so you have to fix the cpu but you can't so you have do something to the bios. It still means the cpu is flawed.

[kalniel]

The cpu is flawed so you have to fix the cpu but you can't so you have do something to the bios. It still means the cpu is flawed.

I don't think it does. If you buy a product and it does what it's supposed to do then it's not flawed. The BIOS fix isn't a workaround, it really is delivering new (and improvedTM) firmware to the CPU. The BIOS is just the delivery mechanism, and I presume once updated you could take the CPU out and use it in a different system no problem, not sure though.

[malfunction]

I presume once updated you could take the CPU out and use it in a different system no problem, not sure though.

I don't believe that's the case - the microcode is loaded by the BIOS and / or OS each time the system boots

[DanceswithUnix]

I don't think it does. If you buy a product and it does what it's supposed to do then it's not flawed. The BIOS fix isn't a workaround, it really is delivering new (and improvedTM) firmware to the CPU. The BIOS is just the delivery mechanism, and I presume once updated you could take the CPU out and use it in a different system no problem, not sure though.

The BIOS can't upload new hardware, so any "fix" can only involve disabling things (possibly putting a slower equivalent in microcode) or changing timings. So you can expect the "fixed" cpu to be slower. Still call it a fix when it isn't good as new?

I don't believe that's the case - the microcode is loaded by the BIOS and / or OS each time the system boots

That is my understanding. I don't think it is flashed into the cpu, it is loaded into fast SRAM.

[fadsarmy]

I don't believe that's the case - the microcode is loaded by the BIOS and / or OS each time the system boots

That's correct, it's like a bootloader. Back to my original question: will the recently manufactured processors (after discovery of bug) still require this fix?

[fadsarmy]

I don't think it does. If you buy a product and it does what it's supposed to do then it's not flawed. The BIOS fix isn't a workaround, it really is delivering new (and improvedTM) firmware to the CPU. The BIOS is just the delivery mechanism, and I presume once updated you could take the CPU out and use it in a different system no problem, not sure though.

You might be actually right after reading this.

[Xlucine]

So there's reprogrammable non-volatile storage on the CPU die?

[Jonatron]

So there's reprogrammable non-volatile storage on the CPU die?

I think it's volatile. The BIOS (and linux kernel sometimes) sends the CPU the microcode on every boot.

[shaithis]

That's correct, it's like a bootloader. Back to my original question: will the recently manufactured processors (after discovery of bug) still require this fix?

You'll probably need to wait for a new stepping to be released, although I cannot remember the last time an etailer listed the stepping.....

Either way, it doesn't really matter. Pretty much every cpu ever released has an errata list, with microcodes updates that fix them.