projects / people / pmueller / ipfire-2.x.git / blame
| Commit | Line | Data |
|---|---|---|
| 2cb7cef9 BS |
1 | From: Takashi Iwai <tiwai@suse.de> |
| 2 | Subject: x86: workaround for mccreary HPET read problem | |
| 3 | Patch-mainline: | |
| 4 | References: bnc#433746 | |
| 5 | ||
| 6 | On mccreacy platform, the read of HPET CMP register seems not updated | |
| 7 | immediately after the write and returns the previous value instead. | |
| 8 | A workaround is to read the register twice. | |
| 9 | ||
| 10 | Signed-off-by: Takashi Iwai <tiwai@suse.de> | |
| 11 | ||
| 12 | --- | |
| 13 | --- a/arch/x86/kernel/hpet.c | |
| 14 | +++ b/arch/x86/kernel/hpet.c | |
| 15 | @@ -278,6 +278,7 @@ static int hpet_legacy_next_event(unsign | |
| 16 | cnt += (u32) delta; | |
| 17 | hpet_writel(cnt, HPET_T0_CMP); | |
| 18 | ||
| 19 | + hpet_readl(HPET_T0_CMP); /* pre-read for bnc#433746 */ | |
| 20 | /* | |
| 21 | * We need to read back the CMP register to make sure that | |
| 22 | * what we wrote hit the chip before we compare it to the |