On 11.05.2022 17:02, Marek Szyprowski wrote: > On 04.05.2022 13:40, Jagan Teki wrote: >> Host transfer() in DSI master will invoke only when the DSI commands >> are sent from DSI devices like DSI Panel or DSI bridges and this >> host transfer wouldn't invoke for I2C-based-DSI bridge drivers. >> >> Handling DSI host initialization in transfer calls misses the >> controller setup for I2C configured DSI bridges. >> >> This patch adds the DSI initialization from transfer to bridge >> pre_enable as the bridge pre_enable API is invoked by core as >> it is common across all classes of DSI device drivers. >> >> v2: >> * check initialized state in samsung_dsim_init >> >> v1: >> * keep DSI init in host transfer >> >> Signed-off-by: Jagan Teki <jagan@xxxxxxxxxxxxxxxxxxxx> > > This doesn't work with Exynos DSI and DSI panels. Here is a bit more > detailed explanation and my solution for this: > > https://lore.kernel.org/all/e96197f9-948a-997e-5453-9f9d179b5f5a@xxxxxxxxxxx/ > I wonder if your modification works on i.MX8MM with a pure DSI-based panel/bridge. In your tree I only see that you have tested it with the i2c-controlled DSI-to-LVDS converter. After the comments from the above mentioned thread I've reworked the initialization again. It looks that the ultimate solution for both worlds is to call samsung_dsim_init() twice, once in pre_enable, then before the first host_transfer, see https://github.com/mszyprow/linux/tree/v5.18-next-20220511-dsi-rework-v2 This way at least it works fine on all my Exynos based test boards. >> --- >> drivers/gpu/drm/bridge/samsung-dsim.c | 18 ++++++++++++------ >> 1 file changed, 12 insertions(+), 6 deletions(-) >> >> diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c >> b/drivers/gpu/drm/bridge/samsung-dsim.c >> index 60dc863113a0..b9361af5ef2d 100644 >> --- a/drivers/gpu/drm/bridge/samsung-dsim.c >> +++ b/drivers/gpu/drm/bridge/samsung-dsim.c >> @@ -1259,6 +1259,9 @@ static int samsung_dsim_init(struct >> samsung_dsim *dsi) >> { >> const struct samsung_dsim_driver_data *driver_data = >> dsi->driver_data; >> + if (dsi->state & DSIM_STATE_INITIALIZED) >> + return 0; >> + >> samsung_dsim_reset(dsi); >> samsung_dsim_enable_irq(dsi); >> @@ -1271,6 +1274,8 @@ static int samsung_dsim_init(struct >> samsung_dsim *dsi) >> samsung_dsim_set_phy_ctrl(dsi); >> samsung_dsim_init_link(dsi); >> + dsi->state |= DSIM_STATE_INITIALIZED; >> + >> return 0; >> } >> @@ -1290,6 +1295,10 @@ static void >> samsung_dsim_atomic_pre_enable(struct drm_bridge *bridge, >> } >> dsi->state |= DSIM_STATE_ENABLED; >> + >> + ret = samsung_dsim_init(dsi); >> + if (ret) >> + return; >> } >> static void samsung_dsim_atomic_enable(struct drm_bridge *bridge, >> @@ -1464,12 +1473,9 @@ static ssize_t >> samsung_dsim_host_transfer(struct mipi_dsi_host *host, >> if (!(dsi->state & DSIM_STATE_ENABLED)) >> return -EINVAL; >> - if (!(dsi->state & DSIM_STATE_INITIALIZED)) { >> - ret = samsung_dsim_init(dsi); >> - if (ret) >> - return ret; >> - dsi->state |= DSIM_STATE_INITIALIZED; >> - } >> + ret = samsung_dsim_init(dsi); >> + if (ret) >> + return ret; >> ret = mipi_dsi_create_packet(&xfer.packet, msg); >> if (ret < 0) > > Best regards Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland
