On Tue, Mar 17, 2015 at 05:22:08PM +0200, Jani Nikula wrote: > On Fri, 13 Mar 2015, ville.syrjala@xxxxxxxxxxxxxxx wrote: > > From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> > > > > When an i2c WRITE gets an i2c defer or short i2c ack reply, we are > > supposed to switch the request from I2C_WRITE to I2C_WRITE_STATUS_UPDATE > > when we continue to poll for the completion of the request. > > As I said IRL, it's a bit unfortunate that setting and resetting of > DP_AUX_I2C_WRITE_STATUS_UPDATE happen at different levels of the > abstraction. But I can live with that. > > We also have another problem with reporting short writes in i915, > hopefully fixed by [1]. Before that gets fixed, can't really r-b. > > BR, > Jani. > > > [1] http://mid.gmane.org/1426605534-5780-1-git-send-email-jani.nikula@xxxxxxxxx BTW I notice now that radeon seems to have that same problem. I won't try to fix that, so just a FYI for the radeon folks... > > > > > Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> > > --- > > drivers/gpu/drm/drm_dp_helper.c | 41 +++++++++++++++++++++++++++++++++++++---- > > 1 file changed, 37 insertions(+), 4 deletions(-) > > > > diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c > > index d5368ea..4db81a6 100644 > > --- a/drivers/gpu/drm/drm_dp_helper.c > > +++ b/drivers/gpu/drm/drm_dp_helper.c > > @@ -422,6 +422,25 @@ static u32 drm_dp_i2c_functionality(struct i2c_adapter *adapter) > > I2C_FUNC_10BIT_ADDR; > > } > > > > +static void drm_dp_i2c_msg_set_request(struct drm_dp_aux_msg *msg, > > + const struct i2c_msg *i2c_msg) > > +{ > > + msg->request = (i2c_msg->flags & I2C_M_RD) ? > > + DP_AUX_I2C_READ : DP_AUX_I2C_WRITE; > > + msg->request |= DP_AUX_I2C_MOT; > > +} > > + > > +static void drm_dp_i2c_msg_write_status_update(struct drm_dp_aux_msg *msg) > > +{ > > + /* > > + * In case of i2c defer or short i2c ack reply to a write, > > + * we need to switch to WRITE_STATUS_UPDATE to drain the > > + * rest of the message > > + */ > > + if ((msg->request & ~DP_AUX_I2C_MOT) == DP_AUX_I2C_WRITE) > > + msg->request |= DP_AUX_I2C_WRITE_STATUS_UPDATE; > > +} > > + > > /* > > * Transfer a single I2C-over-AUX message and handle various error conditions, > > * retrying the transaction as appropriate. It is assumed that the > > @@ -490,6 +509,8 @@ static int drm_dp_i2c_do_msg(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg) > > * Both native ACK and I2C ACK replies received. We > > * can assume the transfer was successful. > > */ > > + if (ret != msg->size) > > + drm_dp_i2c_msg_write_status_update(msg); > > return ret; > > > > case DP_AUX_I2C_REPLY_NACK: > > @@ -501,6 +522,7 @@ static int drm_dp_i2c_do_msg(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg) > > DRM_DEBUG_KMS("I2C defer\n"); > > aux->i2c_defer_count++; > > usleep_range(400, 500); > > + drm_dp_i2c_msg_write_status_update(msg); > > continue; > > > > default: > > @@ -566,10 +588,7 @@ static int drm_dp_i2c_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, > > > > for (i = 0; i < num; i++) { > > msg.address = msgs[i].addr; > > - msg.request = (msgs[i].flags & I2C_M_RD) ? > > - DP_AUX_I2C_READ : > > - DP_AUX_I2C_WRITE; > > - msg.request |= DP_AUX_I2C_MOT; > > + drm_dp_i2c_msg_set_request(&msg, &msgs[i]); > > /* Send a bare address packet to start the transaction. > > * Zero sized messages specify an address only (bare > > * address) transaction. > > @@ -577,6 +596,13 @@ static int drm_dp_i2c_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, > > msg.buffer = NULL; > > msg.size = 0; > > err = drm_dp_i2c_do_msg(aux, &msg); > > + > > + /* > > + * Reset msg.request in case in case it got > > + * changed into a WRITE_STATUS_UPDATE. > > + */ > > + drm_dp_i2c_msg_set_request(&msg, &msgs[i]); > > + > > if (err < 0) > > break; > > /* We want each transaction to be as large as possible, but > > @@ -589,6 +615,13 @@ static int drm_dp_i2c_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, > > msg.size = min(transfer_size, msgs[i].len - j); > > > > err = drm_dp_i2c_drain_msg(aux, &msg); > > + > > + /* > > + * Reset msg.request in case in case it got > > + * changed into a WRITE_STATUS_UPDATE. > > + */ > > + drm_dp_i2c_msg_set_request(&msg, &msgs[i]); > > + > > if (err < 0) > > break; > > transfer_size = err; > > -- > > 2.0.5 > > > > _______________________________________________ > > dri-devel mailing list > > dri-devel@xxxxxxxxxxxxxxxxxxxxx > > http://lists.freedesktop.org/mailman/listinfo/dri-devel > > -- > Jani Nikula, Intel Open Source Technology Center -- Ville Syrjälä Intel OTC _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
