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authorChris Metcalf <cmetcalf@tilera.com>2011-08-02 16:14:02 -0400
committerChris Metcalf <cmetcalf@tilera.com>2011-08-02 16:14:02 -0400
commit3d071cd313643cf82b1ce1ce4fdf08d63ad53964 (patch)
tree874c1683f32f07614aa123f6ca5cf6c2bd443704 /drivers/char
parentcf8e98d15361f8c594da00a3f7a500787fc1a426 (diff)
parent02f8c6aee8df3cdc935e9bdd4f2d020306035dbe (diff)
Merge tag 'v3.0' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6 into for-linus
Diffstat (limited to 'drivers/char')
-rw-r--r--drivers/char/agp/intel-agp.h7
-rw-r--r--drivers/char/hpet.c25
2 files changed, 27 insertions, 5 deletions
diff --git a/drivers/char/agp/intel-agp.h b/drivers/char/agp/intel-agp.h
index 999803ce10dc..5da67f165afa 100644
--- a/drivers/char/agp/intel-agp.h
+++ b/drivers/char/agp/intel-agp.h
@@ -90,9 +90,10 @@
#define G4x_GMCH_SIZE_MASK (0xf << 8)
#define G4x_GMCH_SIZE_1M (0x1 << 8)
#define G4x_GMCH_SIZE_2M (0x3 << 8)
-#define G4x_GMCH_SIZE_VT_1M (0x9 << 8)
-#define G4x_GMCH_SIZE_VT_1_5M (0xa << 8)
-#define G4x_GMCH_SIZE_VT_2M (0xc << 8)
+#define G4x_GMCH_SIZE_VT_EN (0x8 << 8)
+#define G4x_GMCH_SIZE_VT_1M (G4x_GMCH_SIZE_1M | G4x_GMCH_SIZE_VT_EN)
+#define G4x_GMCH_SIZE_VT_1_5M ((0x2 << 8) | G4x_GMCH_SIZE_VT_EN)
+#define G4x_GMCH_SIZE_VT_2M (G4x_GMCH_SIZE_2M | G4x_GMCH_SIZE_VT_EN)
#define GFX_FLSH_CNTL 0x2170 /* 915+ */
diff --git a/drivers/char/hpet.c b/drivers/char/hpet.c
index 051474c65b78..34d6a1cab8de 100644
--- a/drivers/char/hpet.c
+++ b/drivers/char/hpet.c
@@ -163,11 +163,32 @@ static irqreturn_t hpet_interrupt(int irq, void *data)
* This has the effect of treating non-periodic like periodic.
*/
if ((devp->hd_flags & (HPET_IE | HPET_PERIODIC)) == HPET_IE) {
- unsigned long m, t;
+ unsigned long m, t, mc, base, k;
+ struct hpet __iomem *hpet = devp->hd_hpet;
+ struct hpets *hpetp = devp->hd_hpets;
t = devp->hd_ireqfreq;
m = read_counter(&devp->hd_timer->hpet_compare);
- write_counter(t + m, &devp->hd_timer->hpet_compare);
+ mc = read_counter(&hpet->hpet_mc);
+ /* The time for the next interrupt would logically be t + m,
+ * however, if we are very unlucky and the interrupt is delayed
+ * for longer than t then we will completely miss the next
+ * interrupt if we set t + m and an application will hang.
+ * Therefore we need to make a more complex computation assuming
+ * that there exists a k for which the following is true:
+ * k * t + base < mc + delta
+ * (k + 1) * t + base > mc + delta
+ * where t is the interval in hpet ticks for the given freq,
+ * base is the theoretical start value 0 < base < t,
+ * mc is the main counter value at the time of the interrupt,
+ * delta is the time it takes to write the a value to the
+ * comparator.
+ * k may then be computed as (mc - base + delta) / t .
+ */
+ base = mc % t;
+ k = (mc - base + hpetp->hp_delta) / t;
+ write_counter(t * (k + 1) + base,
+ &devp->hd_timer->hpet_compare);
}
if (devp->hd_flags & HPET_SHARED_IRQ)

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