| Message ID | 1503321948-8916-1-git-send-email-shashank.sharma@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, Aug 21, 2017 at 06:55:47PM +0530, Shashank Sharma wrote: > It's an observation during some CI tests that few LSPCON chips > respond slow while system is under load, and need some delay > while reading current mode status using i2c-over-aux channel. > > This patch: > - Adds few retries and delays before declaring a read > failure from LSPCON hardware. > - Changes the debug level of the print from ERROR->DEBUG > whereas another patch in I915 will add an ERROR message > from the caller when we have timed out all our limits. > > V2: addressed review comments from Imre, and added r-b > - use int instead of u8 for counter > - use for loop instead of do...while(); > > Cc: Ville Syrjala <ville.syrjala@linux.intel.com> > Cc: Imre Deak <imre.deak@intel.com> > > Reviewed-by: Imre Deak <imre.deak@intel.com> > Signed-off-by: Shashank Sharma <shashank.sharma@intel.com> > Signed-off-by: Mahesh Kumar <mahesh1.kumar@intel.com> > --- > drivers/gpu/drm/drm_dp_dual_mode_helper.c | 14 +++++++++++--- > 1 file changed, 11 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 80e62f6..fc8c7ac 100644 > --- a/drivers/gpu/drm/drm_dp_dual_mode_helper.c > +++ b/drivers/gpu/drm/drm_dp_dual_mode_helper.c > @@ -409,6 +409,7 @@ int drm_lspcon_get_mode(struct i2c_adapter *adapter, > enum drm_lspcon_mode *mode) > { > u8 data; > + int retry; > int ret = 0; > > if (!mode) { > @@ -417,10 +418,17 @@ 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 = 5; ; retry--) { Ok, confused myself with my original suggestion to include above the condition for retry too. That could add an extraneous delay if all the transfers fail as you explained on IRC. I think this is still a bit clearer than the do {} while() loop so let's go with this version. > + ret = drm_dp_dual_mode_read(adapter, > + DP_DUAL_MODE_LSPCON_CURRENT_MODE, > + &data, sizeof(data)); > + if (!ret || !retry) > + break; > + usleep_range(500, 1000); > + } > + > 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 80e62f6..fc8c7ac 100644 --- a/drivers/gpu/drm/drm_dp_dual_mode_helper.c +++ b/drivers/gpu/drm/drm_dp_dual_mode_helper.c @@ -409,6 +409,7 @@ int drm_lspcon_get_mode(struct i2c_adapter *adapter, enum drm_lspcon_mode *mode) { u8 data; + int retry; int ret = 0; if (!mode) { @@ -417,10 +418,17 @@ 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 = 5; ; retry--) { + ret = drm_dp_dual_mode_read(adapter, + DP_DUAL_MODE_LSPCON_CURRENT_MODE, + &data, sizeof(data)); + if (!ret || !retry) + break; + usleep_range(500, 1000); + } + if (ret < 0) { - DRM_ERROR("LSPCON read(0x80, 0x41) failed\n"); + DRM_DEBUG_KMS("LSPCON read(0x80, 0x41) failed\n"); return -EFAULT; }
It's an observation during some CI tests that few LSPCON chips respond slow while system is under load, and need some delay while reading current mode status using i2c-over-aux channel. This patch: - Adds few retries and delays before declaring a read failure from LSPCON hardware. - Changes the debug level of the print from ERROR->DEBUG whereas another patch in I915 will add an ERROR message from the caller when we have timed out all our limits. V2: addressed review comments from Imre, and added r-b - use int instead of u8 for counter - use for loop instead of do...while(); Cc: Ville Syrjala <ville.syrjala@linux.intel.com> Cc: Imre Deak <imre.deak@intel.com> Reviewed-by: Imre Deak <imre.deak@intel.com> Signed-off-by: Shashank Sharma <shashank.sharma@intel.com> Signed-off-by: Mahesh Kumar <mahesh1.kumar@intel.com> --- drivers/gpu/drm/drm_dp_dual_mode_helper.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-)