Custom Search
Navigation: Linux Kernel Driver DataBase - web LKDDB: Main index - M index
The Linux kernel configuration item CONFIG_MTRR has multiple definitions:
arch/x86/KconfigThe configuration item CONFIG_MTRR:
CONFIG_EXPERTOn Intel P6 family processors (Pentium Pro, Pentium II and later) the Memory Type Range Registers (MTRRs) may be used to control processor access to memory ranges. This is most useful if you have a video (VGA) card on a PCI or AGP bus. Enabling write-combining allows bus write transfers to be combined into a larger transfer before bursting over the PCI/AGP bus. This can increase performance of image write operations 2.5 times or more. Saying Y here creates a /proc/mtrr file which may be used to manipulate your processor's MTRRs. Typically the X server should use this.
This code has a reasonably generic interface so that similar control registers on other processors can be easily supported as well:
The Cyrix 6x86, 6x86MX and M II processors have Address Range Registers (ARRs) which provide a similar functionality to MTRRs. For these, the ARRs are used to emulate the MTRRs. The AMD K6-2 (stepping 8 and above) and K6-3 processors have two MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing write-combining. All of these processors are supported by this code and it makes sense to say Y here if you have one of them.
Saying Y here also fixes a problem with buggy SMP BIOSes which only set the MTRRs for the boot CPU and not for the secondary CPUs. This can lead to all sorts of problems, so it's good to say Y here.
You can safely say Y even if your machine doesn't have MTRRs, you'll just add about 9 KB to your kernel.
See Documentation/arch/x86/mtrr.rst for more information.
arch/x86_64/KconfigThe configuration item CONFIG_MTRR:
(none)On Intel P6 family processors (Pentium Pro, Pentium II and later) the Memory Type Range Registers (MTRRs) may be used to control processor access to memory ranges. This is most useful if you have a video (VGA) card on a PCI or AGP bus. Enabling write-combining allows bus write transfers to be combined into a larger transfer before bursting over the PCI/AGP bus. This can increase performance of image write operations 2.5 times or more. Saying Y here creates a /proc/mtrr file which may be used to manipulate your processor's MTRRs. Typically the X server should use this.
This code has a reasonably generic interface so that similar control registers on other processors can be easily supported as well.
Saying Y here also fixes a problem with buggy SMP BIOSes which only set the MTRRs for the boot CPU and not for the secondary CPUs. This can lead to all sorts of problems, so it's good to say Y here.
Just say Y here, all x86-64 machines support MTRRs.
See Documentation/mtrr.txt for more information.
arch/i386/KconfigThe configuration item CONFIG_MTRR:
(none)On Intel P6 family processors (Pentium Pro, Pentium II and later) the Memory Type Range Registers (MTRRs) may be used to control processor access to memory ranges. This is most useful if you have a video (VGA) card on a PCI or AGP bus. Enabling write-combining allows bus write transfers to be combined into a larger transfer before bursting over the PCI/AGP bus. This can increase performance of image write operations 2.5 times or more. Saying Y here creates a /proc/mtrr file which may be used to manipulate your processor's MTRRs. Typically the X server should use this.
This code has a reasonably generic interface so that similar control registers on other processors can be easily supported as well:
The Cyrix 6x86, 6x86MX and M II processors have Address Range Registers (ARRs) which provide a similar functionality to MTRRs. For these, the ARRs are used to emulate the MTRRs. The AMD K6-2 (stepping 8 and above) and K6-3 processors have two MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing write-combining. All of these processors are supported by this code and it makes sense to say Y here if you have one of them.
Saying Y here also fixes a problem with buggy SMP BIOSes which only set the MTRRs for the boot CPU and not for the secondary CPUs. This can lead to all sorts of problems, so it's good to say Y here.
You can safely say Y even if your machine doesn't have MTRRs, you'll just add about 9 KB to your kernel.
See Documentation/mtrr.txt for more information.
Raw data from LKDDb:
(none)This page is automaticly generated with free (libre, open) software lkddb(see lkddb-sources).
The data is retrived from:
Popular queries:
Navigation: Linux Kernel Driver DataBase - web LKDDB: main index - M index
Automatically generated (in year 2024). See also LKDDb sources on GitLab