| Message ID | 1662999830-13916-4-git-send-email-quic_khsieh@quicinc.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | cleared DP_DOWNSPREAD_CTRL register | expand |
On 12/09/2022 19:23, Kuogee Hsieh wrote: > Bring sink out of D3 (power down) mode into D0 (normal operation) mode > by setting DP_SET_POWER_D0 bit to DP_SET_POWER dpcd register. This > patch will retry 3 times if written to DP_SET_POWER register failed. Could you please elaborate this change? Can the sink succeed in reading the DP_SET_POWER, but fail writing DP_SET_POWER? > > Changes in v5: > -- split into two patches > > Signed-off-by: Kuogee Hsieh <quic_khsieh@quicinc.com> > --- > drivers/gpu/drm/msm/dp/dp_link.c | 13 ++++++++----- > 1 file changed, 8 insertions(+), 5 deletions(-) > > diff --git a/drivers/gpu/drm/msm/dp/dp_link.c b/drivers/gpu/drm/msm/dp/dp_link.c > index 9d5381d..4360728 100644 > --- a/drivers/gpu/drm/msm/dp/dp_link.c > +++ b/drivers/gpu/drm/msm/dp/dp_link.c > @@ -50,6 +50,7 @@ static int dp_aux_link_power_up(struct drm_dp_aux *aux, > { > u8 value; > ssize_t len; > + int i; > > if (link->revision < 0x11) > return 0; > @@ -61,11 +62,13 @@ static int dp_aux_link_power_up(struct drm_dp_aux *aux, > value &= ~DP_SET_POWER_MASK; > value |= DP_SET_POWER_D0; > > - len = drm_dp_dpcd_writeb(aux, DP_SET_POWER, value); > - if (len < 0) > - return len; > - > - usleep_range(1000, 2000); > + /* retry for 1ms to give the sink time to wake up */ > + for (i = 0; i < 3; i++) { > + len = drm_dp_dpcd_writeb(aux, DP_SET_POWER, value); > + usleep_range(1000, 2000); > + if (len == 1) > + break; > + } > > return 0; > }
On 9/12/2022 11:37 AM, Dmitry Baryshkov wrote: > On 12/09/2022 19:23, Kuogee Hsieh wrote: >> Bring sink out of D3 (power down) mode into D0 (normal operation) mode >> by setting DP_SET_POWER_D0 bit to DP_SET_POWER dpcd register. This >> patch will retry 3 times if written to DP_SET_POWER register failed. > > Could you please elaborate this change? Can the sink succeed in > reading the DP_SET_POWER, but fail writing DP_SET_POWER? yes, there is possible since it is not only set local sink device but also all downstream sink devices to D0 state. > >> >> Changes in v5: >> -- split into two patches >> >> Signed-off-by: Kuogee Hsieh <quic_khsieh@quicinc.com> >> --- >> drivers/gpu/drm/msm/dp/dp_link.c | 13 ++++++++----- >> 1 file changed, 8 insertions(+), 5 deletions(-) >> >> diff --git a/drivers/gpu/drm/msm/dp/dp_link.c >> b/drivers/gpu/drm/msm/dp/dp_link.c >> index 9d5381d..4360728 100644 >> --- a/drivers/gpu/drm/msm/dp/dp_link.c >> +++ b/drivers/gpu/drm/msm/dp/dp_link.c >> @@ -50,6 +50,7 @@ static int dp_aux_link_power_up(struct drm_dp_aux >> *aux, >> { >> u8 value; >> ssize_t len; >> + int i; >> if (link->revision < 0x11) >> return 0; >> @@ -61,11 +62,13 @@ static int dp_aux_link_power_up(struct drm_dp_aux >> *aux, >> value &= ~DP_SET_POWER_MASK; >> value |= DP_SET_POWER_D0; >> - len = drm_dp_dpcd_writeb(aux, DP_SET_POWER, value); >> - if (len < 0) >> - return len; >> - >> - usleep_range(1000, 2000); >> + /* retry for 1ms to give the sink time to wake up */ >> + for (i = 0; i < 3; i++) { >> + len = drm_dp_dpcd_writeb(aux, DP_SET_POWER, value); >> + usleep_range(1000, 2000); >> + if (len == 1) >> + break; >> + } >> return 0; >> } >
On 12/09/2022 22:26, Kuogee Hsieh wrote: > > On 9/12/2022 11:37 AM, Dmitry Baryshkov wrote: >> On 12/09/2022 19:23, Kuogee Hsieh wrote: >>> Bring sink out of D3 (power down) mode into D0 (normal operation) mode >>> by setting DP_SET_POWER_D0 bit to DP_SET_POWER dpcd register. This >>> patch will retry 3 times if written to DP_SET_POWER register failed. >> >> Could you please elaborate this change? Can the sink succeed in >> reading the DP_SET_POWER, but fail writing DP_SET_POWER? > > yes, there is possible since it is not only set local sink device but > also all downstream sink devices to D0 state. Ack. Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org> > >> >>> >>> Changes in v5: >>> -- split into two patches >>> >>> Signed-off-by: Kuogee Hsieh <quic_khsieh@quicinc.com> >>> --- >>> drivers/gpu/drm/msm/dp/dp_link.c | 13 ++++++++----- >>> 1 file changed, 8 insertions(+), 5 deletions(-) >>> >>> diff --git a/drivers/gpu/drm/msm/dp/dp_link.c >>> b/drivers/gpu/drm/msm/dp/dp_link.c >>> index 9d5381d..4360728 100644 >>> --- a/drivers/gpu/drm/msm/dp/dp_link.c >>> +++ b/drivers/gpu/drm/msm/dp/dp_link.c >>> @@ -50,6 +50,7 @@ static int dp_aux_link_power_up(struct drm_dp_aux >>> *aux, >>> { >>> u8 value; >>> ssize_t len; >>> + int i; >>> if (link->revision < 0x11) >>> return 0; >>> @@ -61,11 +62,13 @@ static int dp_aux_link_power_up(struct drm_dp_aux >>> *aux, >>> value &= ~DP_SET_POWER_MASK; >>> value |= DP_SET_POWER_D0; >>> - len = drm_dp_dpcd_writeb(aux, DP_SET_POWER, value); >>> - if (len < 0) >>> - return len; >>> - >>> - usleep_range(1000, 2000); >>> + /* retry for 1ms to give the sink time to wake up */ >>> + for (i = 0; i < 3; i++) { >>> + len = drm_dp_dpcd_writeb(aux, DP_SET_POWER, value); >>> + usleep_range(1000, 2000); >>> + if (len == 1) >>> + break; >>> + } >>> return 0; >>> } >>
diff --git a/drivers/gpu/drm/msm/dp/dp_link.c b/drivers/gpu/drm/msm/dp/dp_link.c index 9d5381d..4360728 100644 --- a/drivers/gpu/drm/msm/dp/dp_link.c +++ b/drivers/gpu/drm/msm/dp/dp_link.c @@ -50,6 +50,7 @@ static int dp_aux_link_power_up(struct drm_dp_aux *aux, { u8 value; ssize_t len; + int i; if (link->revision < 0x11) return 0; @@ -61,11 +62,13 @@ static int dp_aux_link_power_up(struct drm_dp_aux *aux, value &= ~DP_SET_POWER_MASK; value |= DP_SET_POWER_D0; - len = drm_dp_dpcd_writeb(aux, DP_SET_POWER, value); - if (len < 0) - return len; - - usleep_range(1000, 2000); + /* retry for 1ms to give the sink time to wake up */ + for (i = 0; i < 3; i++) { + len = drm_dp_dpcd_writeb(aux, DP_SET_POWER, value); + usleep_range(1000, 2000); + if (len == 1) + break; + } return 0; }
Bring sink out of D3 (power down) mode into D0 (normal operation) mode by setting DP_SET_POWER_D0 bit to DP_SET_POWER dpcd register. This patch will retry 3 times if written to DP_SET_POWER register failed. Changes in v5: -- split into two patches Signed-off-by: Kuogee Hsieh <quic_khsieh@quicinc.com> --- drivers/gpu/drm/msm/dp/dp_link.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-)