On Fri, 24 Jan 2020, Anshuman Gupta <anshuman.gupta@xxxxxxxxx> wrote:
> On 2020-01-23 at 15:48:05 +0200, Jani Nikula wrote:
>> On Thu, 23 Jan 2020, Anshuman Gupta <anshuman.gupta@xxxxxxxxx> wrote:
>> > It should not be assumed that a disabled display pipe will be
>> > always last the pipe.
>> > for_each_pipe() should iterate over I915_MAX_PIPES and check
>> > for the disabled pipe and skip that pipe so that it should not
>> > initialize the intel crtc for any disabled pipes.
>> >
>> > Few compilation error needed to handle accordingly due to
>> > change in for_each_pipe() macro.
>>
>> Really? Please paste.
> It is dangling-else warning at couple of places.
> drivers/gpu/drm/i915/i915_irq.c:1861:5: error: suggest explicit braces to avoid ambiguous ‘else’ [-Werror=dangling-else]
> 1861 | if (pch_iir & SDE_FDI_MASK)
> drivers/gpu/drm/i915/i915_irq.c:1944:5: error: suggest explicit braces to avoid ambiguous ‘else’ [-Werror=dangling-else]
> 1944 | if (pch_iir & SDE_FDI_MASK_CPT)
Right, I suppose this is caused by the nesting of the for loops with
if-else.
Perhaps the right course of action is to *not* reuse for_each_pipe() in
for_each_pipe_masked(). Just combine the conditions into one.
BR,
Jani.
>>
>> >
>> > Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
>> > Signed-off-by: Anshuman Gupta <anshuman.gupta@xxxxxxxxx>
>> > ---
>> > drivers/gpu/drm/i915/display/intel_display.h | 5 +++--
>> > drivers/gpu/drm/i915/i915_irq.c | 6 ++++--
>> > 2 files changed, 7 insertions(+), 4 deletions(-)
>> >
>> > diff --git a/drivers/gpu/drm/i915/display/intel_display.h b/drivers/gpu/drm/i915/display/intel_display.h
>> > index 028aab728514..47813a50add4 100644
>> > --- a/drivers/gpu/drm/i915/display/intel_display.h
>> > +++ b/drivers/gpu/drm/i915/display/intel_display.h
>> > @@ -312,10 +312,11 @@ enum phy_fia {
>> > };
>> >
>> > #define for_each_pipe(__dev_priv, __p) \
>> > - for ((__p) = 0; (__p) < INTEL_NUM_PIPES(__dev_priv); (__p)++)
>> > + for ((__p) = 0; (__p) < I915_MAX_PIPES; (__p)++) \
>>
>> Originally I was envisioning using for_each_set_bit() from bitops.h for
>> this. It's probably more efficient, however I'm not sure if efficiency
>> matters much here. The ugly part is that for_each_set_bit() requires an
>> explicit cast to unsigned long *.
>>
>> Perhaps this is just as well, it's not wrong, and can always be updated
>> later.
>>
>> > + for_each_if((INTEL_INFO(__dev_priv)->pipe_mask) & BIT(__p))
>> >
>> > #define for_each_pipe_masked(__dev_priv, __p, __mask) \
>> > - for ((__p) = 0; (__p) < INTEL_NUM_PIPES(__dev_priv); (__p)++) \
>> > + for_each_pipe(__dev_priv, __p) \
>> > for_each_if((__mask) & BIT(__p))
>> >
>> > #define for_each_cpu_transcoder_masked(__dev_priv, __t, __mask) \
>> > diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
>> > index 94cb25ac504d..22ecd5bc407e 100644
>> > --- a/drivers/gpu/drm/i915/i915_irq.c
>> > +++ b/drivers/gpu/drm/i915/i915_irq.c
>> > @@ -1735,11 +1735,12 @@ static void ibx_irq_handler(struct drm_i915_private *dev_priv, u32 pch_iir)
>> > if (pch_iir & SDE_POISON)
>> > DRM_ERROR("PCH poison interrupt\n");
>> >
>> > - if (pch_iir & SDE_FDI_MASK)
>> > + if (pch_iir & SDE_FDI_MASK) {
>> > for_each_pipe(dev_priv, pipe)
>> > DRM_DEBUG_DRIVER(" pipe %c FDI IIR: 0x%08x\n",
>> > pipe_name(pipe),
>> > I915_READ(FDI_RX_IIR(pipe)));
>> > + }
>>
>> Are the brace changes really needed? This is what the for_each_if hack
>> is supposed to tackle.
> IMHO it was dangling-else compilation, warning that requires braces.
> please correct me if i am wrong.
> Thanks,
> Anshuman
>>
>> >
>> > if (pch_iir & (SDE_TRANSB_CRC_DONE | SDE_TRANSA_CRC_DONE))
>> > DRM_DEBUG_DRIVER("PCH transcoder CRC done interrupt\n");
>> > @@ -1818,11 +1819,12 @@ static void cpt_irq_handler(struct drm_i915_private *dev_priv, u32 pch_iir)
>> > if (pch_iir & SDE_AUDIO_CP_CHG_CPT)
>> > DRM_DEBUG_DRIVER("Audio CP change interrupt\n");
>> >
>> > - if (pch_iir & SDE_FDI_MASK_CPT)
>> > + if (pch_iir & SDE_FDI_MASK_CPT) {
>> > for_each_pipe(dev_priv, pipe)
>> > DRM_DEBUG_DRIVER(" pipe %c FDI IIR: 0x%08x\n",
>> > pipe_name(pipe),
>> > I915_READ(FDI_RX_IIR(pipe)));
>> > + }
>> >
>> > if (pch_iir & SDE_ERROR_CPT)
>> > cpt_serr_int_handler(dev_priv);
>>
>> --
>> Jani Nikula, Intel Open Source Graphics Center
--
Jani Nikula, Intel Open Source Graphics Center
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