IRQ Stacks.
Straight_Man
Geeky, in my own wayNaples, FL Icrontian
This will at first sound too advanced, but even XP has some IRQ stack issues. FIX can be done with BIOS in some cases, or device prioritizing with driver tweaks in others.
This will seem to be a bit general, I am trying to guage topical interest on this.
Basicly, the BIOS assigns resources at boot, and can be told to rewrite the CMOS table, and can be forced to talk to any Windows. I will give you a sample case, and how I fixed the quirks that the fix solved all of, and am gonna summarize it. ?Questions welcome, VERY welcome, if put as questions to gain knowledge.
Basicly, when you have an IRQ driven system, it is best fro ultra-smooth operation of box if each device has its own IRQ. BIOS has 4 bits to play with for IRQ numbering. Devices get a logical channel number. They also get RAM space assigned to them-- usually in first MEG of RAM, as far as BIOS is concerned.
Box for case study is like this, and I will be illustrating two stacks on this hardware set....
Board, MSI KT4VL. Video card is a GeForce4 4800 GPU card(Gainward SE, but this is not a video card driver issue alone, it is a stack issue). Board has three onboard USB root hubs. AND an embedded ethernet controller.
BIOS, when asked to deal with this, gened the following stacks:
IRQ5 has the following devices:
Two of the USB root hubs. Realtek audio chip. USB and sound work fine, so I let this stack be (embedded, cannot change).
IRQ11 has the following:
The video card. Ethernet embedded chip. The third USB root hub, this one is the USB2 root hub.
Problems:
Video hang and stagger when using ethernet to go to broadband, from anything, software or browsing, and slow bringup of site pages in any browser.
Fix:
Set ethernet to forced 100Tx mode, do not let it negotiate modes in auto. Video is faster and smoother, and browsing 4X as fast, evn over our virus-clogged internet yesterday. WHY??? BIOS stacks, the NIC was blocked from talking to Windows by video use of IRQ channel.
Now, BIOS stacks still exist. BUT, the following also happened:
Folding is smoother and a bit FASTER. Folding clinet connects with fewer errors. Defragmenter in XP does not lock at 1%. The taskbar icons respond to hover better for tooltips.
Trick??? Force driver to match priority of Windows for kinds of devices. Video card is so dang FAST it can handle intemittent updates and use IRQ channel intermittently. So, by forcing a NIC (embedded) to be in full higher speed mode, Windows matches its internal use of 100 versus 100 instead of having a NIC that internally and driverwise is running at 10 MB while Windows thinks it is running at 100 Mbit per second.
Why did this happen??? XP uses logical IRQs more extensively than the BIOSs do right now, and remaps to logicals up to IRQ 20 to avoid internal conflicts within itself. BUT, BIOS still uses IRQ channeling first and I\O ports within channel to route things. So, if you have a 3-4 high stacked IRQ (and 11 is also used by South Bridge, whihc is not even shown in XPs device conflict list) and you get conflicts and cannot unstack the IRQs with PNP forced IRQ assignments in BIOS, then you get to decide on device priorities.
In my case, 6 clicks fixed: a multitude of issues that would seem to be not at all related to video or ethernet. Among other things, my KVM switch works better also (URK, eeegh, why did I not apply old experiential IRQ-Stacking-makes-for-trouble knowledge SOONER
) and does not completely lock when the Barton box locks VIDEO.
John-- who would be happy to talk about this issue and workable but oddball seeming ways of resolving things, which is still relevant, and which is one of "fix the unfixable boxes" bag of knowledge applied semi-tricks. That is base of why a lot of my oddball off-topic twists to threads actually DO FIX problems if applied as given-- done this kind of stack resolving on about 500 boxes over the years.
This will seem to be a bit general, I am trying to guage topical interest on this.
Basicly, the BIOS assigns resources at boot, and can be told to rewrite the CMOS table, and can be forced to talk to any Windows. I will give you a sample case, and how I fixed the quirks that the fix solved all of, and am gonna summarize it. ?Questions welcome, VERY welcome, if put as questions to gain knowledge.
Basicly, when you have an IRQ driven system, it is best fro ultra-smooth operation of box if each device has its own IRQ. BIOS has 4 bits to play with for IRQ numbering. Devices get a logical channel number. They also get RAM space assigned to them-- usually in first MEG of RAM, as far as BIOS is concerned.
Box for case study is like this, and I will be illustrating two stacks on this hardware set....
Board, MSI KT4VL. Video card is a GeForce4 4800 GPU card(Gainward SE, but this is not a video card driver issue alone, it is a stack issue). Board has three onboard USB root hubs. AND an embedded ethernet controller.
BIOS, when asked to deal with this, gened the following stacks:
IRQ5 has the following devices:
Two of the USB root hubs. Realtek audio chip. USB and sound work fine, so I let this stack be (embedded, cannot change).
IRQ11 has the following:
The video card. Ethernet embedded chip. The third USB root hub, this one is the USB2 root hub.
Problems:
Video hang and stagger when using ethernet to go to broadband, from anything, software or browsing, and slow bringup of site pages in any browser.
Fix:
Set ethernet to forced 100Tx mode, do not let it negotiate modes in auto. Video is faster and smoother, and browsing 4X as fast, evn over our virus-clogged internet yesterday. WHY??? BIOS stacks, the NIC was blocked from talking to Windows by video use of IRQ channel.
Now, BIOS stacks still exist. BUT, the following also happened:
Folding is smoother and a bit FASTER. Folding clinet connects with fewer errors. Defragmenter in XP does not lock at 1%. The taskbar icons respond to hover better for tooltips.
Trick??? Force driver to match priority of Windows for kinds of devices. Video card is so dang FAST it can handle intemittent updates and use IRQ channel intermittently. So, by forcing a NIC (embedded) to be in full higher speed mode, Windows matches its internal use of 100 versus 100 instead of having a NIC that internally and driverwise is running at 10 MB while Windows thinks it is running at 100 Mbit per second.
Why did this happen??? XP uses logical IRQs more extensively than the BIOSs do right now, and remaps to logicals up to IRQ 20 to avoid internal conflicts within itself. BUT, BIOS still uses IRQ channeling first and I\O ports within channel to route things. So, if you have a 3-4 high stacked IRQ (and 11 is also used by South Bridge, whihc is not even shown in XPs device conflict list) and you get conflicts and cannot unstack the IRQs with PNP forced IRQ assignments in BIOS, then you get to decide on device priorities.
In my case, 6 clicks fixed: a multitude of issues that would seem to be not at all related to video or ethernet. Among other things, my KVM switch works better also (URK, eeegh, why did I not apply old experiential IRQ-Stacking-makes-for-trouble knowledge SOONER
) and does not completely lock when the Barton box locks VIDEO.John-- who would be happy to talk about this issue and workable but oddball seeming ways of resolving things, which is still relevant, and which is one of "fix the unfixable boxes" bag of knowledge applied semi-tricks. That is base of why a lot of my oddball off-topic twists to threads actually DO FIX problems if applied as given-- done this kind of stack resolving on about 500 boxes over the years.
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