Re: [PATCH] (Longhaul 1/5) PCI: Protect bus master DMA from Longhaulby rw semaphores

[Rafał Bilski]

> 
> That really is a rather horrible design on their part. Who the hell at
> VIA thought this was a good idea?
> 

I have asked them. Answer is: support is in north/south bridge.
This code works fine (of course "clear BM bit for each device" removed):
[...]
	cx = &pr->power.states[ACPI_STATE_C3];
	printk("Begin..\n"); /* Just to be sure */
	preempt_disable();
	local_irq_save(flags);
[...]
	safe_halt();	/* Sync */

	ACPI_FLUSH_CPU_CACHE();

	wrmsrl(MSR_VIA_LONGHAUL, longhaul->val);
	/* Invoke C3 */
	inb(cx->address);
	/* Dummy op - must do something useless after P_LVL3 read */
	t2 = inl(acpi_fadt.xpm_tmr_blk.address);

	local_irq_disable();
[...]
	printk("..End\n");

30 min "hdparm -t", frequency changes at 1s interval.
CPU temperature is changing too.
Checked in Bashmark.

THIS IS WORKING.


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