On Mon, 21 Mar 2016, Jani Nikula <[email protected]> wrote:
> [ text/plain ]
> On Mon, 21 Mar 2016, Vandana Kannan <[email protected]> wrote:
>> According to the BSpec update, bit 7 of PORT_CL1CM_DW0 register needs to be
>> checked to ensure that the register is in accessible state.
>
> *sigh* the bspec is still not updated, and I didn't get the BUN.
>
>> Also, based on a BSpec update, changing the timeout value to
>> check iphypwrgood, from 10ms to wait for up to 100us.
>>
>> Signed-off-by: Vandana Kannan <[email protected]>
>> Reported-by: Philippe Lecluse <[email protected]>
>> Cc: Deak, Imre <[email protected]>
>> ---
>> drivers/gpu/drm/i915/i915_reg.h | 1 +
>> drivers/gpu/drm/i915/intel_ddi.c | 11 +++++++++--
>> 2 files changed, 10 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/i915_reg.h
>> b/drivers/gpu/drm/i915/i915_reg.h
>> index 7dfc400..9a02bfc 100644
>> --- a/drivers/gpu/drm/i915/i915_reg.h
>> +++ b/drivers/gpu/drm/i915/i915_reg.h
>> @@ -1318,6 +1318,7 @@ enum skl_disp_power_wells {
>> #define _PORT_CL1CM_DW0_A 0x162000
>> #define _PORT_CL1CM_DW0_BC 0x6C000
>> #define PHY_POWER_GOOD (1 << 16)
>> +#define PHY_RESERVED (1 << 7)
>> #define BXT_PORT_CL1CM_DW0(phy) _BXT_PHY((phy),
>> _PORT_CL1CM_DW0_BC, \
>> _PORT_CL1CM_DW0_A)
>>
>> diff --git a/drivers/gpu/drm/i915/intel_ddi.c
>> b/drivers/gpu/drm/i915/intel_ddi.c
>> index 62de9f4..354f949 100644
>> --- a/drivers/gpu/drm/i915/intel_ddi.c
>> +++ b/drivers/gpu/drm/i915/intel_ddi.c
>> @@ -2669,9 +2669,16 @@ static void broxton_phy_init(struct drm_i915_private
>> *dev_priv,
>> val |= GT_DISPLAY_POWER_ON(phy);
>> I915_WRITE(BXT_P_CR_GT_DISP_PWRON, val);
>>
>> - /* Considering 10ms timeout until BSpec is updated */
>> - if (wait_for(I915_READ(BXT_PORT_CL1CM_DW0(phy)) & PHY_POWER_GOOD, 10))
>> + /*
>> + * HW team confirmed that the time to reach phypowergood status is
>> + * anywhere between 50 us and 100us.
>> + */
Interesting, the spec section (now that I found it, thanks again!) says,
"recommended poll time interval = 100 us". Interval, not timeout.
>> + if (wait_for_atomic_us(((!(I915_READ(BXT_PORT_CL1CM_DW0(phy)) &
>> + PHY_RESERVED)) &&
>> + ((I915_READ(BXT_PORT_CL1CM_DW0(phy)) &
>> + PHY_POWER_GOOD) == PHY_POWER_GOOD)), 100)) {
>
> Is there any reason why you'd need to do the read twice? Why not just
> write it as:
>
> (I915_READ(BXT_PORT_CL1CM_DW0(phy)) & (PHY_RESERVED | PHY_POWER_GOOD)) ==
> PHY_POWER_GOOD
AFAICT this should be fine.
BR,
Jani.
>
> BR,
> Jani.
>
>> DRM_ERROR("timeout during PHY%d power on\n", phy);
>> + }
>>
>> for (port = (phy == DPIO_PHY0 ? PORT_B : PORT_A);
>> port <= (phy == DPIO_PHY0 ? PORT_C : PORT_A); port++) {
--
Jani Nikula, Intel Open Source Technology Center
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