@@ -25,6 +25,7 @@
#include <linux/kernel.h>
#include <linux/via-core.h>
+#include <asm/olpc.h>
#include "via_clock.h"
#include "global.h"
#include "debug.h"
@@ -289,6 +290,10 @@ static void dummy_set_pll(struct via_pll_config config)
printk(KERN_INFO "Using undocumented set PLL.\n%s", via_slap);
}
+static void noop_set_clock_state(u8 state)
+{
+}
+
void via_clock_init(struct via_clock *clock, int gfx_chip)
{
switch (gfx_chip) {
@@ -346,4 +351,18 @@ void via_clock_init(struct via_clock *clock, int gfx_chip)
break;
}
+
+ if (machine_is_olpc()) {
+ /* The OLPC XO-1.5 cannot suspend/resume reliably if the
+ * IGA1/IGA2 clocks are set as on or off (memory rot
+ * occasionally happens during suspend under such
+ * configurations).
+ *
+ * The only known stable scenario is to leave this bits as-is,
+ * which in their default states are documented to enable the
+ * clock only when it is needed.
+ */
+ clock->set_primary_clock_state = noop_set_clock_state;
+ clock->set_secondary_clock_state = noop_set_clock_state;
+ }
}
This is a note to let you know that I have just added a patch titled viafb: don't touch clock state on OLPC XO-1.5 to the linux-3.5.y-queue branch of the 3.5.yuz extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.5.yuz tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Herton ------ From 03757f63cadc0a357b6c17a91c6587a2f6fcac7e Mon Sep 17 00:00:00 2001 From: Daniel Drake <dsd@laptop.org> Date: Tue, 4 Sep 2012 11:45:32 -0400 Subject: [PATCH] viafb: don't touch clock state on OLPC XO-1.5 commit 012a1211845eab69a5488d59eb87d24cc518c627 upstream. As detailed in the thread titled "viafb PLL/clock tweaking causes XO-1.5 instability," enabling or disabling the IGA1/IGA2 clocks causes occasional stability problems during suspend/resume cycles on this platform. This is rather odd, as the documentation suggests that clocks have two states (on/off) and the default (stable) configuration is configured to enable the clock only when it is needed. However, explicitly enabling *or* disabling the clock triggers this system instability, suggesting that there is a 3rd state at play here. Leaving the clock enable/disable registers alone solves this problem. This fixes spurious reboots during suspend/resume behaviour introduced by commit b692a63a. Signed-off-by: Daniel Drake <dsd@laptop.org> Signed-off-by: Florian Tobias Schandinat <FlorianSchandinat@gmx.de> Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com> --- drivers/video/via/via_clock.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) -- 1.7.9.5