On Mon, Jun 17, 2024 at 04:23:07PM GMT, Aradhya Bhatia wrote: > Allow the DCS Write FIFO in the cdns-dsi controller to reset before any > DCS packet is transmitted to the DSI sink device. > > The DCS FIFO reset is optional. Not all panels require it. But at > least one of the DSI based panel that uses Ilitek ILI9881C (DSI to DPI > bridge) doesn't work with without this reset. Could you please be more specific, why doesn't it work. Are there any leftover bytes in the FIFO? Is there any additional delay? > > Signed-off-by: Aradhya Bhatia <a-bhatia1@xxxxxx> > --- > drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c b/drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c > index 05d2f4cc50da..87fdd07ca0bc 100644 > --- a/drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c > +++ b/drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c > @@ -1037,6 +1037,9 @@ static ssize_t cdns_dsi_transfer(struct mipi_dsi_host *host, > > cdns_dsi_init_link(dsi); > > + /* Reset the DCS Write FIFO */ > + writel(0x00, dsi->regs + DIRECT_CMD_FIFO_RST); > + > ret = mipi_dsi_create_packet(&packet, msg); > if (ret) > goto out; > -- > 2.34.1 > -- With best wishes Dmitry
