Re: [Intel-gfx] [PATCH v4] drm/i915: Retry HDCP bksv read
On Monday 05 February 2018 10:54 PM, Sean Paul wrote:
On Mon, Feb 05, 2018 at 10:44:41PM +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]
v4:
retry only if bksv is invalid and no error msg on each attempt
[Seanpaul]
Signed-off-by: Ramalingam C
---
drivers/gpu/drm/i915/intel_hdcp.c | 18 +-
1 file changed, 13 insertions(+), 5 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_hdcp.c
b/drivers/gpu/drm/i915/intel_hdcp.c
index cfd13ee8c534..df0dabab97e1 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 +438,19 @@ 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);
- if (ret)
+
+ /* HDCP spec states that we must retry the bksv if it is invalid */
+ for (i = 0; i < 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 == tries) {
+ DRM_ERROR("HDCP failed, Bksv is invalid\n");
return ret;
This will return 0.
oops :-(. Sleepy head it is...
-Ram
- 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
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Re: [Intel-gfx] [PATCH v4] drm/i915: Retry HDCP bksv read
On Mon, Feb 05, 2018 at 10:44:41PM +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]
>
> v4:
> retry only if bksv is invalid and no error msg on each attempt
> [Seanpaul]
>
> Signed-off-by: Ramalingam C
> ---
> drivers/gpu/drm/i915/intel_hdcp.c | 18 +-
> 1 file changed, 13 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_hdcp.c
> b/drivers/gpu/drm/i915/intel_hdcp.c
> index cfd13ee8c534..df0dabab97e1 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 +438,19 @@ 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);
> - if (ret)
> +
> + /* HDCP spec states that we must retry the bksv if it is invalid */
> + for (i = 0; i < 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 == tries) {
> + DRM_ERROR("HDCP failed, Bksv is invalid\n");
> return ret;
This will return 0.
> - 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
>
--
Sean Paul, Software Engineer, Google / Chromium OS
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[Intel-gfx] [PATCH v4] drm/i915: Retry HDCP bksv read
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]
v4:
retry only if bksv is invalid and no error msg on each attempt
[Seanpaul]
Signed-off-by: Ramalingam C
---
drivers/gpu/drm/i915/intel_hdcp.c | 18 +-
1 file changed, 13 insertions(+), 5 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_hdcp.c
b/drivers/gpu/drm/i915/intel_hdcp.c
index cfd13ee8c534..df0dabab97e1 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 +438,19 @@ 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);
- if (ret)
+
+ /* HDCP spec states that we must retry the bksv if it is invalid */
+ for (i = 0; i < 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 == tries) {
+ DRM_ERROR("HDCP failed, Bksv is invalid\n");
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
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