| Message ID | 1517609350-10698-5-git-send-email-ramalingam.c@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Sat, Feb 03, 2018 at 03:39:06AM +0530, Ramalingam C wrote: > HDCP specification says that when bksv is identified as invalid > (not with 20 1s), bksv should be re-read and verified. > > This patch adds the above mentioned re-read for bksv. > > v2: > Rephrased the commit msg [Seanpaul] > > v3: > do-while to for-loop [Seanpaul] > > Signed-off-by: Ramalingam C <ramalingam.c@intel.com> > --- > drivers/gpu/drm/i915/intel_hdcp.c | 19 +++++++++++++++---- > 1 file changed, 15 insertions(+), 4 deletions(-) > > diff --git a/drivers/gpu/drm/i915/intel_hdcp.c b/drivers/gpu/drm/i915/intel_hdcp.c > index cfd13ee8c534..b1047dbf3393 100644 > --- a/drivers/gpu/drm/i915/intel_hdcp.c > +++ b/drivers/gpu/drm/i915/intel_hdcp.c > @@ -397,7 +397,7 @@ static int intel_hdcp_auth(struct intel_digital_port *intel_dig_port, > struct drm_i915_private *dev_priv; > enum port port; > unsigned long r0_prime_gen_start; > - int ret, i; > + int ret, i, tries = 2; > union { > u32 reg[2]; > u8 shim[DRM_HDCP_AN_LEN]; > @@ -438,11 +438,22 @@ static int intel_hdcp_auth(struct intel_digital_port *intel_dig_port, > r0_prime_gen_start = jiffies; > > memset(&bksv, 0, sizeof(bksv)); > - ret = shim->read_bksv(intel_dig_port, bksv.shim); > + > + /* When bksv is invalid, HDCP spec expects a re-read for bksv */ > + for (i = 0; i < tries; i++) { > + ret = shim->read_bksv(intel_dig_port, bksv.shim); > + if (!ret) { > + if (intel_hdcp_is_ksv_valid(bksv.shim)) { > + break; > + } else { > + DRM_ERROR("Invalid BKSV\n"); > + ret = -ENODEV; > + } > + } > + } Hmm, this is different from what I proposed in a couple of ways: - This will print an ERROR for each failed attempt, which I don't think is needed - If shim->read_bksv fails, we shouldn't need to retry. The retry here should only catch invalid ksv. The shim implementation is responsible for retrying if the link is prone to failure. For a refresher, this is what I proposed in the first review (I added an error): /* HDCP spec states that we must retry the bksv if it is invalid */ for (i = 0; i < bksv_tries; i++) { ret = shim->read_bksv(intel_dig_port, bksv.shim); if (ret) return ret; if (intel_hdcp_is_ksv_valid(bksv.shim)) break; } if (i == bksv_tries) { DRM_ERROR("HDCP failed, Bksv is invalid\n"); return -ENODEV; } > + > if (ret) > return ret; > - else if (!intel_hdcp_is_ksv_valid(bksv.shim)) > - return -ENODEV; > > I915_WRITE(PORT_HDCP_BKSVLO(port), bksv.reg[0]); > I915_WRITE(PORT_HDCP_BKSVHI(port), bksv.reg[1]); > -- > 2.7.4 >
diff --git a/drivers/gpu/drm/i915/intel_hdcp.c b/drivers/gpu/drm/i915/intel_hdcp.c index cfd13ee8c534..b1047dbf3393 100644 --- a/drivers/gpu/drm/i915/intel_hdcp.c +++ b/drivers/gpu/drm/i915/intel_hdcp.c @@ -397,7 +397,7 @@ static int intel_hdcp_auth(struct intel_digital_port *intel_dig_port, struct drm_i915_private *dev_priv; enum port port; unsigned long r0_prime_gen_start; - int ret, i; + int ret, i, tries = 2; union { u32 reg[2]; u8 shim[DRM_HDCP_AN_LEN]; @@ -438,11 +438,22 @@ static int intel_hdcp_auth(struct intel_digital_port *intel_dig_port, r0_prime_gen_start = jiffies; memset(&bksv, 0, sizeof(bksv)); - ret = shim->read_bksv(intel_dig_port, bksv.shim); + + /* When bksv is invalid, HDCP spec expects a re-read for bksv */ + for (i = 0; i < tries; i++) { + ret = shim->read_bksv(intel_dig_port, bksv.shim); + if (!ret) { + if (intel_hdcp_is_ksv_valid(bksv.shim)) { + break; + } else { + DRM_ERROR("Invalid BKSV\n"); + ret = -ENODEV; + } + } + } + if (ret) return ret; - else if (!intel_hdcp_is_ksv_valid(bksv.shim)) - return -ENODEV; I915_WRITE(PORT_HDCP_BKSVLO(port), bksv.reg[0]); I915_WRITE(PORT_HDCP_BKSVHI(port), bksv.reg[1]);
HDCP specification says that when bksv is identified as invalid (not with 20 1s), bksv should be re-read and verified. This patch adds the above mentioned re-read for bksv. v2: Rephrased the commit msg [Seanpaul] v3: do-while to for-loop [Seanpaul] Signed-off-by: Ramalingam C <ramalingam.c@intel.com> --- drivers/gpu/drm/i915/intel_hdcp.c | 19 +++++++++++++++---- 1 file changed, 15 insertions(+), 4 deletions(-)