From b7e59246bae75c301f6005208eb10d738f28b338 Mon Sep 17 00:00:00 2001 From: "Jerry (Fangzhi) Zuo" Date: Thu, 5 Mar 2020 13:10:01 -0800 Subject: [PATCH] ANDROID: drm: Add support for DP 1.4 Compliance edid corruption test Unlike DP 1.2 edid corruption test, DP 1.4 requires to calculate real CRC value of the last edid data block, and write it back. Current edid CRC calculates routine adds the last CRC byte, and check if non-zero. This behavior is not accurate; actually, we need to return the actual CRC value when corruption is detected. This commit changes this issue by returning the calculated CRC, and initiate the required sequence. Change since v7 - Fix for CI.CHECKPATCH Change since v6 - Add return check Change since v5 - Obtain real CRC value before dumping bad edid Change since v4 - Fix for CI.CHECKPATCH Change since v3 - Fix a minor typo. Change since v2 - Rewrite checksum computation routine to avoid duplicated code. - Rename to avoid confusion. Change since v1 - Have separate routine for returning real CRC. Change-Id: I6a67007357e5176994f54c4f30c07f42a2d57bd7 Signed-off-by: Jerry (Fangzhi) Zuo Reviewed-by: Harry Wentland Reviewed-by: Rodrigo Siqueira [abhinavk: resolved conflict with android-5.4's drm_dp_helper.h] Bug: 139653858 Link: https://patchwork.kernel.org/patch/11375865/ Signed-off-by: Abhinav Kumar --- drivers/gpu/drm/drm_dp_helper.c | 59 +++++++++++++++++++++++++++++++++ drivers/gpu/drm/drm_edid.c | 24 +++++++++++--- include/drm/drm_connector.h | 6 ++++ include/drm/drm_dp_helper.h | 2 ++ 4 files changed, 87 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c index ffc68d305afe..8b6dd549f301 100644 --- a/drivers/gpu/drm/drm_dp_helper.c +++ b/drivers/gpu/drm/drm_dp_helper.c @@ -336,6 +336,65 @@ int drm_dp_dpcd_read_link_status(struct drm_dp_aux *aux, } EXPORT_SYMBOL(drm_dp_dpcd_read_link_status); +/** + * drm_dp_send_real_edid_checksum() - send back real edid checksum value + * @aux: DisplayPort AUX channel + * @real_edid_checksum: real edid checksum for the last block + * + * Returns: + * True on success + */ +bool drm_dp_send_real_edid_checksum(struct drm_dp_aux *aux, + u8 real_edid_checksum) +{ + u8 link_edid_read = 0, auto_test_req = 0, test_resp = 0; + + if (drm_dp_dpcd_read(aux, DP_DEVICE_SERVICE_IRQ_VECTOR, + &auto_test_req, 1) < 1) { + DRM_ERROR("DPCD failed read at register 0x%x\n", + DP_DEVICE_SERVICE_IRQ_VECTOR); + return false; + } + auto_test_req &= DP_AUTOMATED_TEST_REQUEST; + + if (drm_dp_dpcd_read(aux, DP_TEST_REQUEST, &link_edid_read, 1) < 1) { + DRM_ERROR("DPCD failed read at register 0x%x\n", + DP_TEST_REQUEST); + return false; + } + link_edid_read &= DP_TEST_LINK_EDID_READ; + + if (!auto_test_req || !link_edid_read) { + DRM_DEBUG_KMS("Source DUT does not support TEST_EDID_READ\n"); + return false; + } + + if (drm_dp_dpcd_write(aux, DP_DEVICE_SERVICE_IRQ_VECTOR, + &auto_test_req, 1) < 1) { + DRM_ERROR("DPCD failed write at register 0x%x\n", + DP_DEVICE_SERVICE_IRQ_VECTOR); + return false; + } + + /* send back checksum for the last edid extension block data */ + if (drm_dp_dpcd_write(aux, DP_TEST_EDID_CHECKSUM, + &real_edid_checksum, 1) < 1) { + DRM_ERROR("DPCD failed write at register 0x%x\n", + DP_TEST_EDID_CHECKSUM); + return false; + } + + test_resp |= DP_TEST_EDID_CHECKSUM_WRITE; + if (drm_dp_dpcd_write(aux, DP_TEST_RESPONSE, &test_resp, 1) < 1) { + DRM_ERROR("DPCD failed write at register 0x%x\n", + DP_TEST_RESPONSE); + return false; + } + + return true; +} +EXPORT_SYMBOL(drm_dp_send_real_edid_checksum); + /** * drm_dp_link_probe() - probe a DisplayPort link for capabilities * @aux: DisplayPort AUX channel diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c index 86603562dba2..e734742486c7 100644 --- a/drivers/gpu/drm/drm_edid.c +++ b/drivers/gpu/drm/drm_edid.c @@ -1358,11 +1358,22 @@ static int validate_displayid(u8 *displayid, int length, int idx); static int drm_edid_block_checksum(const u8 *raw_edid) { int i; - u8 csum = 0; - for (i = 0; i < EDID_LENGTH; i++) + u8 csum = 0, crc = 0; + + for (i = 0; i < EDID_LENGTH - 1; i++) csum += raw_edid[i]; - return csum; + crc = 0x100 - csum; + + return crc; +} + +static bool drm_edid_block_checksum_diff(const u8 *raw_edid, u8 real_checksum) +{ + if (raw_edid[EDID_LENGTH - 1] != real_checksum) + return true; + else + return false; } static bool drm_edid_is_zero(const u8 *in_edid, int length) @@ -1420,7 +1431,7 @@ bool drm_edid_block_valid(u8 *raw_edid, int block, bool print_bad_edid, } csum = drm_edid_block_checksum(raw_edid); - if (csum) { + if (drm_edid_block_checksum_diff(raw_edid, csum)) { if (edid_corrupt) *edid_corrupt = true; @@ -1561,6 +1572,11 @@ static void connector_bad_edid(struct drm_connector *connector, u8 *edid, int num_blocks) { int i; + u8 num_of_ext = edid[0x7e]; + + /* Calculate real checksum for the last edid extension block data */ + connector->real_edid_checksum = + drm_edid_block_checksum(edid + num_of_ext * EDID_LENGTH); if (connector->bad_edid_counter++ && !(drm_debug & DRM_UT_KMS)) return; diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h index 555d16fb383b..d1dd028b33fa 100644 --- a/include/drm/drm_connector.h +++ b/include/drm/drm_connector.h @@ -1401,6 +1401,12 @@ struct drm_connector { * rev1.1 4.2.2.6 */ bool edid_corrupt; + /** + * @real_edid_checksum: real edid checksum for corrupted edid block. + * Required in Displayport 1.4 compliance testing + * rev1.1 4.2.2.6 + */ + u8 real_edid_checksum; /** @debugfs_entry: debugfs directory for this connector */ struct dentry *debugfs_entry; diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h index 8b4ff9f26c32..02ecfdc47bd9 100644 --- a/include/drm/drm_dp_helper.h +++ b/include/drm/drm_dp_helper.h @@ -1361,6 +1361,8 @@ static inline ssize_t drm_dp_dpcd_writeb(struct drm_dp_aux *aux, int drm_dp_dpcd_read_link_status(struct drm_dp_aux *aux, u8 status[DP_LINK_STATUS_SIZE]); +bool drm_dp_send_real_edid_checksum(struct drm_dp_aux *aux, + u8 real_edid_checksum); /* * DisplayPort link */