2010/11/6 Rajat Sharma <fs.rajat@xxxxxxxxx>: > 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 -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx Please read the FAQ at http://kernelnewbies.org/FAQ
