Compaq Research Labs is not and never was banned from posting patches to him. If you look at rmk's latest patches you will see that he merged quite some Ipaq specific stuff.
I know what you're talking about: a year ago there was a flamewar going on about the SA1100 serial drivers between Russell and Compaq's George France. Both are pretty strong characters, and at a certain point Russell posted that he would put CRL in his personal killfile. At that point I stepped in and stopped the flamewar.
The serial driver stuff is pretty much resolved right now, it even had a positive ending: the serial drivers in linux-2.5 will almost certainly be based on the ideas that arose after this accident.
Your gcc remark is also not true. If you look up the "possible compiler bug" thread in the
linux-arm mailing list archive, you can read that he uses Red Hat's gcc-2.96-80 to compile kernels.
I'm glad you like Nicolas Pitre's work, but as you might now Nico only maintains the SA-11x0 port (and works on the XScale). Russell maintains the complete ARM Linux tree, so as you can see Russell and Nico have to work pretty close together. They also pretty much agree on the linux-arm* mailing lists
The good news for you is that Russell integrated quite a large amount of Nico's patch in his latest kernels. See rmk's changelog.
The XScale was certainly not running on its breaking point, we had it only running at a mere 400 MHz because getting it to run at all was much more important that running at full speed.
Oh, floating point emulation has been a part of ARM Linux for ages.
The IQ80310 can be used as a PCI host with a passive PCI backplane, but it can also be used as a normal PCI card in a PC (or whatever else with a PCI bus).
Because we didn't have a passive PCI backplane in New York, MontaVista bought the cheapest PC available at a local computer store and we used that as a backplane. I have no idea what kind of PC it was, we just used it as backplane and power supply to get the XScale running. The PC was definitively worth its price:-)
No, that's not what it means. Nico has been working on this for quite some time (sponsored by MontaVista), but he still maintains the SA1100 Linux tree. I am still working on the LART.
Nico and I have been sharing a hotel room during the Linux World Expo in New York, and we wanted to have the XScale shown running on the expo. So we hacked on thursday night and showed the result on friday.
About the UCB1200 driver: there is a unified UCB1200 driver in Nico's latest SA1100 patch. I promised to review it, but still got no time to do it. I'll do it Real Soon Now [tm].
No. Intel just started shipping the 80200, while the Jornada 820 already exists for quite some time. If a certain device isn't supported by Linux it is usually because the vendor refuses to give away programming information.
One of the main reasons the Compaq iPaq has been successful in the Linux market is that Compaq opened up all programming information and actively participates on the iPaq mailing lists.
Yes, this is indeed the same XScale core that can run up to 1GHz (I don't have exact power figures for that speed, though).
No, this particular CPU (the 80200) is not the comparable to the SA-1110 as used in the Compaq iPaq. The SA-1110 has a lot of IO on board, like two serial ports, IrDA, USB client, LCD controller, PCMCIA controller, etc. The 80200 is more comparable to the SA-110 as used in the Netwinder.
Answer #1: No, ARM and Thumb are not mutually exclusive, they can be mixed in a single program. As far as I know Thumb can also be used in kernel mode.
Answer #2: Yes, GCC supports thumb, though the upcoming GCC-3.0 supports it much better than GCC-2.95.x.
Answer #3: I don't know the Atmel 91AT, but AFAIK the XScale is the first CPU that implements the ARM v5 instruction set. So the answer is: the XScale is an ARM v5 CPU, while the 91AT is (probably) ARM v4.
Remember that the XScale is an embedded CPU, not a general purpose CPU. Embedded devices should be low power, having a full blown FPU makes no sense on such devices.
On the other hand, the XScale also implements the ARM v5 DSP extensions, so it can be used for signal processing.
The main issues were the architecture specific start code, interrupts, memory management. Oh, and some small changes in the MTD drivers to support the XScale.
Slashdot Mirror
You should get your facts right.
Compaq Research Labs is not and never was banned from posting patches to him. If you look at rmk's latest patches you will see that he merged quite some Ipaq specific stuff.
I know what you're talking about: a year ago there was a flamewar going on about the SA1100 serial drivers between Russell and Compaq's George France. Both are pretty strong characters, and at a certain point Russell posted that he would put CRL in his personal killfile. At that point I stepped in and stopped the flamewar.
The serial driver stuff is pretty much resolved right now, it even had a positive ending: the serial drivers in linux-2.5 will almost certainly be based on the ideas that arose after this accident.
Your gcc remark is also not true. If you look up the "possible compiler bug" thread in the linux-arm mailing list archive, you can read that he uses Red Hat's gcc-2.96-80 to compile kernels.
I'm glad you like Nicolas Pitre's work, but as you might now Nico only maintains the SA-11x0 port (and works on the XScale). Russell maintains the complete ARM Linux tree, so as you can see Russell and Nico have to work pretty close together. They also pretty much agree on the linux-arm* mailing lists
The good news for you is that Russell integrated quite a large amount of Nico's patch in his latest kernels. See rmk's changelog.
You misunderstood something. The GPL protects you against patent claims, the BSD license doesn't.
If you take some BSD code and GPL it, you must be pretty damn sure that it's not patented code. Not many people want to take that bet.
The XScale was certainly not running on its breaking point, we had it only running at a mere 400 MHz because getting it to run at all was much more important that running at full speed.
Oh, floating point emulation has been a part of ARM Linux for ages.
Erik
Yup, we used the Intel IQ80310.
:-)
The IQ80310 can be used as a PCI host with a passive PCI backplane, but it can also be used as a normal PCI card in a PC (or whatever else with a PCI bus).
Because we didn't have a passive PCI backplane in New York, MontaVista bought the cheapest PC available at a local computer store and we used that as a backplane. I have no idea what kind of PC it was, we just used it as backplane and power supply to get the XScale running. The PC was definitively worth its price
Erik
No, that's not what it means. Nico has been working on this for quite some time (sponsored by MontaVista), but he still maintains the SA1100 Linux tree. I am still working on the LART.
Nico and I have been sharing a hotel room during the Linux World Expo in New York, and we wanted to have the XScale shown running on the expo. So we hacked on thursday night and showed the result on friday.
About the UCB1200 driver: there is a unified UCB1200 driver in Nico's latest SA1100 patch. I promised to review it, but still got no time to do it. I'll do it Real Soon Now [tm].
Erik
No. Intel just started shipping the 80200, while the Jornada 820 already exists for quite some time. If a certain device isn't supported by Linux it is usually because the vendor refuses to give away programming information.
One of the main reasons the Compaq iPaq has been successful in the Linux market is that Compaq opened up all programming information and actively participates on the iPaq mailing lists.
Erik
Yes and no.
Yes, this is indeed the same XScale core that can run up to 1GHz (I don't have exact power figures for that speed, though).
No, this particular CPU (the 80200) is not the comparable to the SA-1110 as used in the Compaq iPaq. The SA-1110 has a lot of IO on board, like two serial ports, IrDA, USB client, LCD controller, PCMCIA controller, etc. The 80200 is more comparable to the SA-110 as used in the Netwinder.
Erik
Answer #1: No, ARM and Thumb are not mutually exclusive, they can be mixed in a single program. As far as I know Thumb can also be used in kernel mode.
Answer #2: Yes, GCC supports thumb, though the upcoming GCC-3.0 supports it much better than GCC-2.95.x.
Answer #3: I don't know the Atmel 91AT, but AFAIK the XScale is the first CPU that implements the ARM v5 instruction set. So the answer is: the XScale is an ARM v5 CPU, while the 91AT is (probably) ARM v4.
Erik
Remember that the XScale is an embedded CPU, not a general purpose CPU. Embedded devices should be low power, having a full blown FPU makes no sense on such devices.
On the other hand, the XScale also implements the ARM v5 DSP extensions, so it can be used for signal processing.
Erik
The main issues were the architecture specific start code, interrupts, memory management. Oh, and some small changes in the MTD drivers to support the XScale.
Erik