Hi Romain,
On 08-03-2017 08:15, Romain Perier wrote: > Currently, the irq handler that monitores changes for HPD anx RX_SENSE > relies on the status of the bridge for updating the status of the HPD. > The update is done only when the bridge is enabled. > > However, on Rockchip platforms we have found use cases where it could be > a problem. When HDMI is being used, turning off/on the screen or > unplugging/re-plugging the cable, the following simplified code path > will happen: > > - dw_hdmi_irq() will be triggered by an HPD event, as the bridge is on > hdmi->disabled is false, then the handler will update the rxsense flag > accordingly. > - dw_hdmi_update_power() will be invoked with the mode > DRM_FORCE_UNSPECIFIED and rxsense == 1, so dw_hdmi_poweroff() will be > called and the PHY will be desactivated (its pixel clocks and TMDS) > > [...] > > - dw_hdmi_bridge_disable() will be invoked, the bridge will be marked as > disabled. > > - dw_hdmi_irq() will be triggered by an HPD event, as the bridge is > currently disabled the HPD status won't be updated, so hdmi->rxsense > won't be changed. Even if the data part of the PHY is disabled, this > information coming from the HDMI Transmitter is correct and should be > saved. > > [...] > > - dw_hdmi_bridge_enable() will be invoked, the bridge will be marked as > enabled. > - dw_hdmi_update_power() will be called. As hdmi->force will be equal to > DRM_FORCE_UNSPECIFIED the function will rely on hdmi->rxsense. This > field has not been updated by the irq handler, so it will be false and > DRM_FORCE_ON won't be put to hdmi->force. > > Consequently, most of the time dw_hdmi_poweron() won't be called in this > use case, TMDS won't be re-enabled the PHY won't be re-initialized, > resulting in a "Signal not found". > > This commit fixes the issue by removing the check for "!hdmi->disabled". > As already explained, even if the PHY is partially disabled, information > coming from HDMI Transmitter about HPD should be saved for a later use. > > Signed-off-by: Romain Perier <[email protected]> > --- > > Note: Due to an email configuration issue, some of my patches were not > received on infradead.org or vger.kernel.org. It is now fixed, so I > resend this patch for this reason. > > drivers/gpu/drm/bridge/dw-hdmi.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/bridge/dw-hdmi.c > b/drivers/gpu/drm/bridge/dw-hdmi.c > index 235ce7d..b621fc7 100644 > --- a/drivers/gpu/drm/bridge/dw-hdmi.c > +++ b/drivers/gpu/drm/bridge/dw-hdmi.c > @@ -1790,7 +1790,7 @@ static irqreturn_t dw_hdmi_irq(int irq, void *dev_id) > if (intr_stat & > (HDMI_IH_PHY_STAT0_RX_SENSE | HDMI_IH_PHY_STAT0_HPD)) { > mutex_lock(&hdmi->mutex); > - if (!hdmi->disabled && !hdmi->force) { > + if (!hdmi->force) { > /* > * If the RX sense status indicates we're disconnected, > * clear the software rxsense status. Makes sense but I think you need to make sure that phy will not be enabled when bridge is disabled i.e. you should update rxsense only. Best regards, Jose Miguel Abreu _______________________________________________ dri-devel mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/dri-devel
