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Ji-Ze Hong (Peter Hong) authored
Some BIOS only use _OSI("Linux") to distinguish between Linux & Windows. Apply Level/Low to UART trigger mode if Windows, Edge/High mode otherwise. But since 2.6.23 the mainline kernel no longer returns true for _OSI(“Linux”). The default IRQ0~15 trigger mode in Linux is Edge/High mode without ACPI MADT override. It mismatches IRQ mode and makes UART malfunctional on such motherboard. This patch will check the current IRQ mode and apply correct mode to UART. The following link is F81216AD spec PDF: http://html.alldatasheet.com/html-pdf/257956/FINTEK/F81216AD/5569/ 25/F81216AD.html LDN0~3 70h: IRQ channel & Mode register Bit 6~5 : 00 : Active low level mode 01 : Active high edge mode Bit 4 : Sharing Flag (0: not share/1: share) Bit 3~0 : IRQ channel Signed-off-by:
Ji-Ze Hong (Peter Hong) <hpeter+linux_kernel@gmail.com> Signed-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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