| Message ID | 1507630064-17908-2-git-send-email-shashank.sharma@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, Oct 10, 2017 at 03:37:42PM +0530, Shashank Sharma wrote: > From the CI builds, its been observed that during a driver > reload/insert, dp dual mode read function sometimes fails to > read from LSPCON device over i2c-over-aux channel. > > This patch: > - adds some delay and few retries, allowing a scope for these > devices to settle down and respond. > - changes one error log's level from ERROR->DEBUG as we want > to call it an error only after all the retries are exhausted. > > V2: Addressed review comments from Jani (for loop for retry) > V3: Addressed review comments from Imre (break on partial read too) > V3: Addressed review comments from Ville/Imre (Add the retries > exclusively for LSPCON, not for all dp_dual_mode devices) > > Cc: Ville Syrjala <ville.syrjala@linux.intel.com> > Cc: Imre Deak <imre.deak@intel.com> > Cc: Jani Nikula <jani.nikula@linux.intel.com> > Signed-off-by: Shashank Sharma <shashank.sharma@intel.com> Reviewed-by: Imre Deak <imre.deak@intel.com> > --- > drivers/gpu/drm/drm_dp_dual_mode_helper.c | 16 +++++++++++++--- > 1 file changed, 13 insertions(+), 3 deletions(-) > > diff --git a/drivers/gpu/drm/drm_dp_dual_mode_helper.c b/drivers/gpu/drm/drm_dp_dual_mode_helper.c > index 0ef9011..02a5092 100644 > --- a/drivers/gpu/drm/drm_dp_dual_mode_helper.c > +++ b/drivers/gpu/drm/drm_dp_dual_mode_helper.c > @@ -410,6 +410,7 @@ int drm_lspcon_get_mode(struct i2c_adapter *adapter, > { > u8 data; > int ret = 0; > + int retry; > > if (!mode) { > DRM_ERROR("NULL input\n"); > @@ -417,10 +418,19 @@ int drm_lspcon_get_mode(struct i2c_adapter *adapter, > } > > /* Read Status: i2c over aux */ > - ret = drm_dp_dual_mode_read(adapter, DP_DUAL_MODE_LSPCON_CURRENT_MODE, > - &data, sizeof(data)); > + for (retry = 0; retry < 6; retry++) { > + if (retry) > + usleep_range(500, 1000); > + > + ret = drm_dp_dual_mode_read(adapter, > + DP_DUAL_MODE_LSPCON_CURRENT_MODE, > + &data, sizeof(data)); > + if (!ret) > + break; > + } > + > if (ret < 0) { > - DRM_ERROR("LSPCON read(0x80, 0x41) failed\n"); > + DRM_DEBUG_KMS("LSPCON read(0x80, 0x41) failed\n"); > return -EFAULT; > } > > -- > 2.7.4 >
diff --git a/drivers/gpu/drm/drm_dp_dual_mode_helper.c b/drivers/gpu/drm/drm_dp_dual_mode_helper.c index 0ef9011..02a5092 100644 --- a/drivers/gpu/drm/drm_dp_dual_mode_helper.c +++ b/drivers/gpu/drm/drm_dp_dual_mode_helper.c @@ -410,6 +410,7 @@ int drm_lspcon_get_mode(struct i2c_adapter *adapter, { u8 data; int ret = 0; + int retry; if (!mode) { DRM_ERROR("NULL input\n"); @@ -417,10 +418,19 @@ int drm_lspcon_get_mode(struct i2c_adapter *adapter, } /* Read Status: i2c over aux */ - ret = drm_dp_dual_mode_read(adapter, DP_DUAL_MODE_LSPCON_CURRENT_MODE, - &data, sizeof(data)); + for (retry = 0; retry < 6; retry++) { + if (retry) + usleep_range(500, 1000); + + ret = drm_dp_dual_mode_read(adapter, + DP_DUAL_MODE_LSPCON_CURRENT_MODE, + &data, sizeof(data)); + if (!ret) + break; + } + if (ret < 0) { - DRM_ERROR("LSPCON read(0x80, 0x41) failed\n"); + DRM_DEBUG_KMS("LSPCON read(0x80, 0x41) failed\n"); return -EFAULT; }
From the CI builds, its been observed that during a driver reload/insert, dp dual mode read function sometimes fails to read from LSPCON device over i2c-over-aux channel. This patch: - adds some delay and few retries, allowing a scope for these devices to settle down and respond. - changes one error log's level from ERROR->DEBUG as we want to call it an error only after all the retries are exhausted. V2: Addressed review comments from Jani (for loop for retry) V3: Addressed review comments from Imre (break on partial read too) V3: Addressed review comments from Ville/Imre (Add the retries exclusively for LSPCON, not for all dp_dual_mode devices) Cc: Ville Syrjala <ville.syrjala@linux.intel.com> Cc: Imre Deak <imre.deak@intel.com> Cc: Jani Nikula <jani.nikula@linux.intel.com> Signed-off-by: Shashank Sharma <shashank.sharma@intel.com> --- drivers/gpu/drm/drm_dp_dual_mode_helper.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-)