On Sat, 13 Sep 2014, Rodrigo Vivi <rodrigo.vivi at intel.com> wrote:
> In some cases like when PSR just got enabled the panel need more vblank
> times to calculate CRC. I figured that out with the new PSR test cases
> facing some cases that I had a green screen but a blank CRC. Even with
> 2 vblank waits on kernel + 2 vblank waits on test case.
>
> So let's give up to 6 vblank wait time. However we now check for
> TEST_CRC_COUNT that shows when panel finished to calculate CRC and
> has it ready.
>
> Signed-off-by: Rodrigo Vivi <rodrigo.vivi at intel.com>
> ---
> drivers/gpu/drm/i915/intel_dp.c | 20 ++++++++++++++------
> include/drm/drm_dp_helper.h | 5 +++--
> 2 files changed, 17 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index f79473b..eda6467 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -3468,21 +3468,29 @@ int intel_dp_sink_crc(struct intel_dp *intel_dp, u8
> *crc)
> struct drm_device *dev = intel_dig_port->base.base.dev;
> struct intel_crtc *intel_crtc =
> to_intel_crtc(intel_dig_port->base.base.crtc);
> - u8 buf[1];
> + u8 buf;
> + int test_crc_count;
> + int attempts = 6;
>
> - if (drm_dp_dpcd_readb(&intel_dp->aux, DP_TEST_SINK_MISC, buf) < 0)
> + if (drm_dp_dpcd_readb(&intel_dp->aux, DP_TEST_SINK_MISC, &buf) < 0)
> return -EAGAIN;
>
> - if (!(buf[0] & DP_TEST_CRC_SUPPORTED))
> + if (!(buf & DP_TEST_CRC_SUPPORTED))
> return -ENOTTY;
>
> + test_crc_count = buf & DP_TEST_COUNT_MASK;
> +
> if (drm_dp_dpcd_writeb(&intel_dp->aux, DP_TEST_SINK,
> DP_TEST_SINK_START) < 0)
> return -EAGAIN;
>
> - /* Wait 2 vblanks to be sure we will have the correct CRC value */
> - intel_wait_for_vblank(dev, intel_crtc->pipe);
> - intel_wait_for_vblank(dev, intel_crtc->pipe);
> + do {
> + drm_dp_dpcd_readb(&intel_dp->aux, DP_TEST_SINK_MISC, &buf);
> + intel_wait_for_vblank(dev, intel_crtc->pipe);
> + } while(attempts-- && (buf & DP_TEST_COUNT_MASK) <= test_crc_count);
> +
> + if (attempts == 0)
> + return -EAGAIN;
If the do-while stops because of attempts, we'll never end up here
because of the post-decrement. (We'll only return -EAGAIN here if the
other condition does not hold at precisely attempts == 1 before the
post-decrement.)
BR,
Jani.
>
> if (drm_dp_dpcd_read(&intel_dp->aux, DP_TEST_CRC_R_CR, crc, 6) < 0)
> return -EAGAIN;
> diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
> index 9305c71..8edeed0 100644
> --- a/include/drm/drm_dp_helper.h
> +++ b/include/drm/drm_dp_helper.h
> @@ -303,7 +303,8 @@
> #define DP_TEST_CRC_B_CB 0x244
>
> #define DP_TEST_SINK_MISC 0x246
> -#define DP_TEST_CRC_SUPPORTED (1 << 5)
> +# define DP_TEST_CRC_SUPPORTED (1 << 5)
> +# define DP_TEST_COUNT_MASK 0x7
>
> #define DP_TEST_RESPONSE 0x260
> # define DP_TEST_ACK (1 << 0)
> @@ -313,7 +314,7 @@
> #define DP_TEST_EDID_CHECKSUM 0x261
>
> #define DP_TEST_SINK 0x270
> -#define DP_TEST_SINK_START (1 << 0)
> +# define DP_TEST_SINK_START (1 << 0)
>
> #define DP_PAYLOAD_TABLE_UPDATE_STATUS 0x2c0 /* 1.2 MST */
> # define DP_PAYLOAD_TABLE_UPDATED (1 << 0)
> --
> 1.9.3
>
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> Intel-gfx at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
--
Jani Nikula, Intel Open Source Technology Center
