On Mon, Feb 12, 2018 at 11:19:09AM +0000, Chris Wilson wrote: > Quoting Imre Deak (2018-02-08 18:44:41) > > On Thu, Feb 08, 2018 at 06:33:03PM +0000, Chris Wilson wrote: > > > Quoting Imre Deak (2018-02-08 17:41:02) > > > > On BXT/GLK GEN6_PCODE_READ_RC6VIDS fails with > > > > MAILBOX_P24C_CC_ILLEGAL_CMD, so don't try to do the query on these > > > > platforms. Do it only on SNB, IVB and HSW, where we use this command > > > > anyway for RC6 enabling. > > > > > > > > Based on my tests the command also succeeds on all LLC platforms, but > > > > it's not clear if it's really supported on those (it returns 0 aka 245mv > > > > for all RC6 states everywhere except on SNB). BSpec lists the command as > > > > supported on SKL+ (see P24C_PCODE_MAILBOX_INTERFACE) but that's clearly > > > > incorrect, since on SKL/KBL the same command ID is used for > > > > SKL_PCODE_LOAD_HDCP_KEYS. Since the command fails on BXT/GLK, the BSpec > > > > command list is also incorrect for those platforms (see > > > > P_CR_P24C_PCODE_MAILBOX_INTERFACE_0_2_0_GTTMMADR). > > > > > > > > I filed a request to update that info in Bspec, but for now let's > > > > assume a minimal set of platforms where the command is supported. > > > > > > > > Reference: https://bugs.freedesktop.org/show_bug.cgi?id=103337 > > > > Signed-off-by: Imre Deak <imre.d...@intel.com> > > > > --- > > > > drivers/gpu/drm/i915/i915_debugfs.c | 24 +++++++++++++++--------- > > > > 1 file changed, 15 insertions(+), 9 deletions(-) > > > > > > > > diff --git a/drivers/gpu/drm/i915/i915_debugfs.c > > > > b/drivers/gpu/drm/i915/i915_debugfs.c > > > > index 2bdce9fea671..8f9045fae3cf 100644 > > > > --- a/drivers/gpu/drm/i915/i915_debugfs.c > > > > +++ b/drivers/gpu/drm/i915/i915_debugfs.c > > > > @@ -1484,9 +1484,12 @@ static int gen6_drpc_info(struct seq_file *m) > > > > gen9_powergate_status = > > > > I915_READ(GEN9_PWRGT_DOMAIN_STATUS); > > > > } > > > > > > > > - mutex_lock(&dev_priv->pcu_lock); > > > > - sandybridge_pcode_read(dev_priv, GEN6_PCODE_READ_RC6VIDS, > > > > &rc6vids); > > > > - mutex_unlock(&dev_priv->pcu_lock); > > > > + if (INTEL_GEN(dev_priv) <= 7) { > > > > + mutex_lock(&dev_priv->pcu_lock); > > > > + sandybridge_pcode_read(dev_priv, > > > > GEN6_PCODE_READ_RC6VIDS, > > > > + &rc6vids); > > > > + mutex_unlock(&dev_priv->pcu_lock); > > > > + } > > > > > > > > seq_printf(m, "RC1e Enabled: %s\n", > > > > yesno(rcctl1 & GEN6_RC_CTL_RC1e_ENABLE)); > > > > @@ -1542,12 +1545,15 @@ static int gen6_drpc_info(struct seq_file *m) > > > > print_rc6_res(m, "RC6+ residency since boot:", > > > > GEN6_GT_GFX_RC6p); > > > > print_rc6_res(m, "RC6++ residency since boot:", > > > > GEN6_GT_GFX_RC6pp); > > > > > > > > - seq_printf(m, "RC6 voltage: %dmV\n", > > > > - GEN6_DECODE_RC6_VID(((rc6vids >> 0) & 0xff))); > > > > - seq_printf(m, "RC6+ voltage: %dmV\n", > > > > - GEN6_DECODE_RC6_VID(((rc6vids >> 8) & 0xff))); > > > > - seq_printf(m, "RC6++ voltage: %dmV\n", > > > > - GEN6_DECODE_RC6_VID(((rc6vids >> 16) & 0xff))); > > > > + if (INTEL_GEN(dev_priv) <= 7) { > > > > > > I expect this will confuse gcc-4.4 and it will emit a > > > maybe-used-uninitialised. I would set rc6vids=0 and then test if > > > (rc6vids) here. > > > > It's inited already to 0, so shouldn't warn. (0 is a valid value > > otherwise). > > (Valid but not validated ;)
True, so we don't know if the platforms returning 0 (with the PCODE command otherwise succeeding) return an actually correct value. Checking again it's only SNB where we use the value (so not even IVB/HSW) and that's the only one returning a non-zero value. I hope someone will follow-up on my bspec update request and clarify this. > > Reviewed-by: Chris Wilson <ch...@chris-wilson.co.uk> > -Chris _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx
