On Friday 30 March 2012 03:59 PM, Santosh Shilimkar wrote:
On Friday 30 March 2012 03:53 PM, Cousson, Benoit wrote:
On 3/30/2012 10:44 AM, Santosh Shilimkar wrote:
On Friday 30 March 2012 02:04 PM, Archit Taneja wrote:
On Friday 30 March 2012 02:01 PM, Santosh Shilimkar wrote:
+ Kevin
On Friday 30 March 2012 01:56 PM, Tomi Valkeinen wrote:
On Fri, 2012-03-30 at 13:51 +0530, Shilimkar, Santosh wrote:
On Fri, Mar 30, 2012 at 1:37 PM, Tomi
Valkeinen<tomi.valkeinen@xxxxxx> wrote:
All OMAP4 versions seem to be affected. I couldn't find a mention
about
this in the mainline kernel. Any ideas how and where this should be
fixed?
It's not patched for mainline. Generally clock-domain code
is abstracted from drivers but considering the errata and affected
modules, I guees it should be handled by DSS driver
since that is where the state of DSS or ISS will be known. Note
ISS will be automatically taken care since it will always use
disaplay.
In internal tree's this was handled as part of DSS early
suspend/resume
That version doesn't work as it uses functions that are not
exported to
drivers.
I don't know much about the clock domain code, but I hope there's a
way
to handle it there. Otherwise I guess I need to add a new set of
platform callback functions, so that the dss driver can call
arch/arm/mach-omap2 code to enable and disable the work-around. I
dislike that because I'm currently trying to remove those kinds of
hacks
to make dss work better with DT =).
I agree. In fact I faced similar issue when I briefly tried moving
OMAP cpuidle code to drivers/idle/*.
That time me and Kevin concluded that till we move the powerdomain,
clockdomain code to drivers/* and export it, the cpuidle movement
needs to be deferred.
How about preventing the issue to occur by keeping DSS and ISS in
No-standby mode for the affected OMAP versions. The errata says:
"Such a situation can occur when the impacted initiator is generating
short MStandby pulses (pulse durations less than one L4 clock cycle)"
Chaning the mstandby hwmod data for DSS and ISS would prevent the need
for exporting these clock domain functions only for this errata.
That will just break PM :-)
Not at all. At least it will not be worst than the current WA.
I think Archit is right, at least this is the exact same question I'm
asking to the designers :-).
Am not sure what do you mean by here. What Archit said is statitically
setting up DSS/ISS sysnconfig to no standby. It will definitely break
PM.
The WA was doing runtime this with clockdomain APIs. If you say manage
the sysconfig runtime in driver, then it will work.
I had a general PRCM question regarding this. If an initiator is
disabled (i.e, clocks are OFF and Power state is OFF), then would the
PRCM even care to look at the IdleAck/Mstandby signal of that initiator?
Or in other words, look at what the initiator had programmed in it's
SYSCONFIG register. If it does consider them, it seems like that's bad
HW design!
Archit
With this change DSS will never assert standby and then PRCM can never
send idle-req to modules. Indirectly no power transitions.
This is exactly what will happen if you set the clock domain in NO_IDLE.
So in any case, you cannot have autoidle during the
Guess I was not clear. The idea was to put CD in no_idle
when DSS active and allow idle when not active.
Looks like you saying OK to hack sysconfig for which we have
been pushing back on drivers not to do it. Ofcourse errata
and various reset bugs have broken that rule anyways.
Regards
Santosh
Regards
santosh
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