From f93dd508afc19262fd95c01520d5d6d7937be4e8 Mon Sep 17 00:00:00 2001 From: Thierry Reding Date: Tue, 5 Aug 2014 11:30:14 +0200 Subject: [PATCH] drm/dsi: Always use low-power mode for DCS commands Many peripherals require DCS commands to be sent in low power mode and will fail to correctly process them in high speed mode. Section 5.2 of the MIPI DSI specification also mandates that on bidirectional lanes, data shall be transmitted in low power mode only. At worst this change will make transmission of DCS commands slower than optimal on some DSI peripherals, but it should enable DCS commands to be successfully transmitted to any DSI peripheral. If transmission in low power mode turns out to be too slow at some point in the future, one possible solution would be to explicitly mark devices that support high speed transmission of DCS commands. Signed-off-by: Thierry Reding --- drivers/gpu/drm/drm_mipi_dsi.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/gpu/drm/drm_mipi_dsi.c b/drivers/gpu/drm/drm_mipi_dsi.c index b0a304ab6827..57588b9ff7c6 100644 --- a/drivers/gpu/drm/drm_mipi_dsi.c +++ b/drivers/gpu/drm/drm_mipi_dsi.c @@ -370,6 +370,7 @@ ssize_t mipi_dsi_dcs_write_buffer(struct mipi_dsi_device *dsi, { struct mipi_dsi_msg msg = { .channel = dsi->channel, + .flags = MIPI_DSI_MSG_USE_LPM, .tx_buf = data, .tx_len = len }; @@ -457,6 +458,7 @@ ssize_t mipi_dsi_dcs_write(struct mipi_dsi_device *dsi, u8 cmd, } memset(&msg, 0, sizeof(msg)); + msg.flags = MIPI_DSI_MSG_USE_LPM; msg.channel = dsi->channel; msg.tx_len = size; msg.tx_buf = tx; @@ -501,6 +503,7 @@ ssize_t mipi_dsi_dcs_read(struct mipi_dsi_device *dsi, u8 cmd, void *data, struct mipi_dsi_msg msg = { .channel = dsi->channel, .type = MIPI_DSI_DCS_READ, + .flags = MIPI_DSI_MSG_USE_LPM, .tx_buf = &cmd, .tx_len = 1, .rx_buf = data, -- 2.0.4