Greg, > So the timing as to when the parameters is not what I was addressing.
>From your previous reply, it looked like you are not agreeing with my first statement "As I can remember, Linux uses BIOS only at the bootup time, after that on a running kernel, there is no role of BIOS routines." so this bootup time code involves all these sort of initialization, perhaps I used 'bootup time' as very abstract word. I think we are on same page. BTW with your reply, looks you are also in storage domain. Rajat 2010/11/6 Greg Freemyer <[email protected]> > 2010/11/6 Rajat Sharma <[email protected]>: > > Greg, > > you are right about Intel AHCI, I also had to change it once in BIOS for > > detecting some Intel's SSD drives. But I think that was again for boot > time > > hardware initialization. Are you sure that these parameters are accessed > > from BIOS routines on a running Linux kernel? > > Rajat > > > > Rajat, > > The OP said "I am just exploring how much the linux is dependent on BIOS." > > So the timing as to when the parameters is not what I was addressing. > > I am saying that there are BIOS controlled parameters such as PCI ID > that impact linux in a fundamental way because they drive which ATA > driver is used. > > Then further there are BIOS settings that are read by the kernel that > impact the operation of the drivers. That the parameters are only > read from the BIOS area on startup doesn't change the fact they impact > the operation during the entire time linux is running. > > Note, while many BIOS parameters are used exclusively only for startup > hardware initialization, the ones I am referring to are used to > control the logic flow of the driver code in many routine operational > situations. > > One simple example is for a fake-raid sata controller that implements > a meta-data area at the start of the disk in certain modes, but not > all. The linux driver for this must interrogate the system to > determine which mode the controller card is in and then set an > internal offset field to ensure that "sector 0" is what it is expected > to be. > > If this is not done, then if the system is booted into Windows with a > dual-boot, the offsets will be wrong and everything falls apart in a > major way. > > You might argue this is not a "BIOS" setting, but with many > motherboards today, the SATA controller is built in and the BIOS > directly controls which mode the controller operates in. Thus I would > call this a situation where "linux is dependent on BIOS". > > Greg >
