Hello,
Early experimentation on my part seems to show that it is possible to
put an ICH SATA controller booted in SATA compatibility mode in full
native AHCI mode. The drawback of having the ICH7 chip in AHCI mode is
that the PATA ports are not claimed or used by any driver, rendering the
PATA ports unusable.
Suggestion:
Make a new driver (ata_hci7 ?) which claims the following IDs (all
vendor 8086/intel):
27c0: Desktop ICH7 SATA, IDE mode
27c1: Desktop ICH7 SATA, AHCI mode
27c4: Mobile ICH7 SATA, IDE mode
27c5: Mobile ICH7 SATA, AHCI mode
Driver initialization would be as follows:
1. Claim the device for itself
2. If the SATA chip is in IDE mode, initialize AHCI mode.
3. Use functions in ahci.ko to enable AHCI functionality (will need some
EXPORT_SYMBOL_GPL).
4. Use the functions in ata_piix.ko to enable PATA functionality (more
EXPORT_SYMBOL_GPL).
On driver unload, the driver would put back the controller in IDE mode
if it was before module load.
Such a driver would provide enhanced performance for users who cannot
enable AHCI for their machine in the bios. It would also mean that ICH7
users would be able to use AHCI along with PATA.
Example (and current testing) system:
- Dell Latitude D620
SATA P0: main disk drive
SATA P2: external SATA ?
PATA Secondary master "hdc": DVD-Rom ejectable drive bay.
Please let me know what you think,
Thank you,
Jonathan
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