| Message ID | 20180504221800.17830-2-matthew.s.atwood@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, May 04, 2018 at 03:18:00PM -0700, matthew.s.atwood@intel.com wrote: > From: Matt Atwood <matthew.s.atwood@intel.com> > > DP_TRAINING_AUX_RD_INTERVAL with DP 1.3 spec changed bit scheeme from 8 > bits to 7 in DPCD 0x000e. The 8th bit is used to identify extended > receiver capabilities. For panels that use this new feature wait interval > would be increased by 512 ms, when spec is max 16 ms. This behavior is > described in table 2-158 of DP 1.4 spec address 0000eh. > > With the introduction of DP 1.4 spec main link clock recovery was > standardized to 100 us regardless of TRAINING_AUX_RD_INTERVAL value. > > To avoid breaking panels that are not spec compiant we now warn on > invalid values. > > V2: commit title/message, masking all 7 bits, warn on out of spec values. > V3: commit message, make link train clock recovery follow DP 1.4 spec. > V4: style changes > V5: typo > V6: print statement revisions, DP_REV to DPCD_REV, comment correction > V7: typo > V8: Style > V9: Strip out DPCD_REV_XX into seperate patch > v10: DPCD_REV_XX to DP_DPCD_REV_XX > > Signed-off-by: Matt Atwood <matthew.s.atwood@intel.com> > Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com> patches pushed to drm-misc-next. Thanks, Rodrigo. > --- > drivers/gpu/drm/drm_dp_helper.c | 22 ++++++++++++++++++---- > include/drm/drm_dp_helper.h | 1 + > 2 files changed, 19 insertions(+), 4 deletions(-) > > diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c > index ffe14ec3e7f2..36c7609a4bd5 100644 > --- a/drivers/gpu/drm/drm_dp_helper.c > +++ b/drivers/gpu/drm/drm_dp_helper.c > @@ -119,18 +119,32 @@ u8 drm_dp_get_adjust_request_pre_emphasis(const u8 link_status[DP_LINK_STATUS_SI > EXPORT_SYMBOL(drm_dp_get_adjust_request_pre_emphasis); > > void drm_dp_link_train_clock_recovery_delay(const u8 dpcd[DP_RECEIVER_CAP_SIZE]) { > - if (dpcd[DP_TRAINING_AUX_RD_INTERVAL] == 0) > + int rd_interval = dpcd[DP_TRAINING_AUX_RD_INTERVAL] & > + DP_TRAINING_AUX_RD_MASK; > + > + if (rd_interval > 4) > + DRM_DEBUG_KMS("AUX interval %d, out of range (max 4)\n", > + rd_interval); > + > + if (rd_interval == 0 || dpcd[DP_DPCD_REV] >= DP_DPCD_REV_14) > udelay(100); > else > - mdelay(dpcd[DP_TRAINING_AUX_RD_INTERVAL] * 4); > + mdelay(rd_interval * 4); > } > EXPORT_SYMBOL(drm_dp_link_train_clock_recovery_delay); > > void drm_dp_link_train_channel_eq_delay(const u8 dpcd[DP_RECEIVER_CAP_SIZE]) { > - if (dpcd[DP_TRAINING_AUX_RD_INTERVAL] == 0) > + int rd_interval = dpcd[DP_TRAINING_AUX_RD_INTERVAL] & > + DP_TRAINING_AUX_RD_MASK; > + > + if (rd_interval > 4) > + DRM_DEBUG_KMS("AUX interval %d, out of range (max 4)\n", > + rd_interval); > + > + if (rd_interval == 0) > udelay(400); > else > - mdelay(dpcd[DP_TRAINING_AUX_RD_INTERVAL] * 4); > + mdelay(rd_interval * 4); > } > EXPORT_SYMBOL(drm_dp_link_train_channel_eq_delay); > > diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h > index 96dcef479ed6..ecf3e2bf293b 100644 > --- a/include/drm/drm_dp_helper.h > +++ b/include/drm/drm_dp_helper.h > @@ -124,6 +124,7 @@ > # define DP_DPCD_DISPLAY_CONTROL_CAPABLE (1 << 3) /* edp v1.2 or higher */ > > #define DP_TRAINING_AUX_RD_INTERVAL 0x00e /* XXX 1.2? */ > +# define DP_TRAINING_AUX_RD_MASK 0x7F /* XXX 1.2? */ > > #define DP_ADAPTER_CAP 0x00f /* 1.2 */ > # define DP_FORCE_LOAD_SENSE_CAP (1 << 0) > -- > 2.17.0 >
diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c index ffe14ec3e7f2..36c7609a4bd5 100644 --- a/drivers/gpu/drm/drm_dp_helper.c +++ b/drivers/gpu/drm/drm_dp_helper.c @@ -119,18 +119,32 @@ u8 drm_dp_get_adjust_request_pre_emphasis(const u8 link_status[DP_LINK_STATUS_SI EXPORT_SYMBOL(drm_dp_get_adjust_request_pre_emphasis); void drm_dp_link_train_clock_recovery_delay(const u8 dpcd[DP_RECEIVER_CAP_SIZE]) { - if (dpcd[DP_TRAINING_AUX_RD_INTERVAL] == 0) + int rd_interval = dpcd[DP_TRAINING_AUX_RD_INTERVAL] & + DP_TRAINING_AUX_RD_MASK; + + if (rd_interval > 4) + DRM_DEBUG_KMS("AUX interval %d, out of range (max 4)\n", + rd_interval); + + if (rd_interval == 0 || dpcd[DP_DPCD_REV] >= DP_DPCD_REV_14) udelay(100); else - mdelay(dpcd[DP_TRAINING_AUX_RD_INTERVAL] * 4); + mdelay(rd_interval * 4); } EXPORT_SYMBOL(drm_dp_link_train_clock_recovery_delay); void drm_dp_link_train_channel_eq_delay(const u8 dpcd[DP_RECEIVER_CAP_SIZE]) { - if (dpcd[DP_TRAINING_AUX_RD_INTERVAL] == 0) + int rd_interval = dpcd[DP_TRAINING_AUX_RD_INTERVAL] & + DP_TRAINING_AUX_RD_MASK; + + if (rd_interval > 4) + DRM_DEBUG_KMS("AUX interval %d, out of range (max 4)\n", + rd_interval); + + if (rd_interval == 0) udelay(400); else - mdelay(dpcd[DP_TRAINING_AUX_RD_INTERVAL] * 4); + mdelay(rd_interval * 4); } EXPORT_SYMBOL(drm_dp_link_train_channel_eq_delay); diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h index 96dcef479ed6..ecf3e2bf293b 100644 --- a/include/drm/drm_dp_helper.h +++ b/include/drm/drm_dp_helper.h @@ -124,6 +124,7 @@ # define DP_DPCD_DISPLAY_CONTROL_CAPABLE (1 << 3) /* edp v1.2 or higher */ #define DP_TRAINING_AUX_RD_INTERVAL 0x00e /* XXX 1.2? */ +# define DP_TRAINING_AUX_RD_MASK 0x7F /* XXX 1.2? */ #define DP_ADAPTER_CAP 0x00f /* 1.2 */ # define DP_FORCE_LOAD_SENSE_CAP (1 << 0)