On Wed, Jul 19, 2023 at 12:05 AM Frieder Schrempf <frieder.schrempf@xxxxxxxxxx> wrote: > > Hi Tim, > > On 19.07.23 01:03, Tim Harvey wrote: > > On Thu, Jul 13, 2023 at 3:01 AM Frieder Schrempf > > <frieder.schrempf@xxxxxxxxxx> wrote: > >> > >> Hi Tim, > >> > >> On 13.07.23 09:18, Frieder Schrempf wrote: > >>> Hi Tim, > >>> > >>> On 13.07.23 00:34, Tim Harvey wrote: > >>>> On Wed, May 3, 2023 at 9:33 AM Frieder Schrempf <frieder@xxxxxxx> wrote: > >>>>> > >>>>> From: Frieder Schrempf <frieder.schrempf@xxxxxxxxxx> > >>>>> > >>>>> According to the documentation [1] the proper enable flow is: > >>>>> > >>>>> 1. Enable DSI link and keep data lanes in LP-11 (stop state) > >>>>> 2. Disable stop state to bring data lanes into HS mode > >>>>> > >>>>> Currently we do this all at once within enable(), which doesn't > >>>>> allow to meet the requirements of some downstream bridges. > >>>>> > >>>>> To fix this we now enable the DSI in pre_enable() and force it > >>>>> into stop state using the FORCE_STOP_STATE bit in the ESCMODE > >>>>> register until enable() is called where we reset the bit. > >>>>> > >>>>> We currently do this only for i.MX8M as Exynos uses a different > >>>>> init flow where samsung_dsim_init() is called from > >>>>> samsung_dsim_host_transfer(). > >>>>> > >>>>> [1] https://docs.kernel.org/gpu/drm-kms-helpers.html#mipi-dsi-bridge-operation > >>>>> > >>>>> Signed-off-by: Frieder Schrempf <frieder.schrempf@xxxxxxxxxx> > >>>>> --- > >>>>> Changes for v2: > >>>>> * Drop RFC > >>>>> --- > >>>>> drivers/gpu/drm/bridge/samsung-dsim.c | 25 +++++++++++++++++++++++-- > >>>>> 1 file changed, 23 insertions(+), 2 deletions(-) > >>>>> > >>>>> diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c b/drivers/gpu/drm/bridge/samsung-dsim.c > >>>>> index e0a402a85787..9775779721d9 100644 > >>>>> --- a/drivers/gpu/drm/bridge/samsung-dsim.c > >>>>> +++ b/drivers/gpu/drm/bridge/samsung-dsim.c > >>>>> @@ -859,6 +859,10 @@ static int samsung_dsim_init_link(struct samsung_dsim *dsi) > >>>>> reg = samsung_dsim_read(dsi, DSIM_ESCMODE_REG); > >>>>> reg &= ~DSIM_STOP_STATE_CNT_MASK; > >>>>> reg |= DSIM_STOP_STATE_CNT(driver_data->reg_values[STOP_STATE_CNT]); > >>>>> + > >>>>> + if (!samsung_dsim_hw_is_exynos(dsi->plat_data->hw_type)) > >>>>> + reg |= DSIM_FORCE_STOP_STATE; > >>>>> + > >>>>> samsung_dsim_write(dsi, DSIM_ESCMODE_REG, reg); > >>>>> > >>>>> reg = DSIM_BTA_TIMEOUT(0xff) | DSIM_LPDR_TIMEOUT(0xffff); > >>>>> @@ -1340,6 +1344,9 @@ static void samsung_dsim_atomic_pre_enable(struct drm_bridge *bridge, > >>>>> ret = samsung_dsim_init(dsi); > >>>>> if (ret) > >>>>> return; > >>>>> + > >>>>> + samsung_dsim_set_display_mode(dsi); > >>>>> + samsung_dsim_set_display_enable(dsi, true); > >>>>> } > >>>>> } > >>>>> > >>>>> @@ -1347,9 +1354,16 @@ static void samsung_dsim_atomic_enable(struct drm_bridge *bridge, > >>>>> struct drm_bridge_state *old_bridge_state) > >>>>> { > >>>>> struct samsung_dsim *dsi = bridge_to_dsi(bridge); > >>>>> + u32 reg; > >>>>> > >>>>> - samsung_dsim_set_display_mode(dsi); > >>>>> - samsung_dsim_set_display_enable(dsi, true); > >>>>> + if (samsung_dsim_hw_is_exynos(dsi->plat_data->hw_type)) { > >>>>> + samsung_dsim_set_display_mode(dsi); > >>>>> + samsung_dsim_set_display_enable(dsi, true); > >>>>> + } else { > >>>>> + reg = samsung_dsim_read(dsi, DSIM_ESCMODE_REG); > >>>>> + reg &= ~DSIM_FORCE_STOP_STATE; > >>>>> + samsung_dsim_write(dsi, DSIM_ESCMODE_REG, reg); > >>>>> + } > >>>>> > >>>>> dsi->state |= DSIM_STATE_VIDOUT_AVAILABLE; > >>>>> } > >>>>> @@ -1358,10 +1372,17 @@ static void samsung_dsim_atomic_disable(struct drm_bridge *bridge, > >>>>> struct drm_bridge_state *old_bridge_state) > >>>>> { > >>>>> struct samsung_dsim *dsi = bridge_to_dsi(bridge); > >>>>> + u32 reg; > >>>>> > >>>>> if (!(dsi->state & DSIM_STATE_ENABLED)) > >>>>> return; > >>>>> > >>>>> + if (!samsung_dsim_hw_is_exynos(dsi->plat_data->hw_type)) { > >>>>> + reg = samsung_dsim_read(dsi, DSIM_ESCMODE_REG); > >>>>> + reg |= DSIM_FORCE_STOP_STATE; > >>>>> + samsung_dsim_write(dsi, DSIM_ESCMODE_REG, reg); > >>>>> + } > >>>>> + > >>>>> dsi->state &= ~DSIM_STATE_VIDOUT_AVAILABLE; > >>>>> } > >>>>> > >>>>> -- > >>>>> 2.40.0 > >>>>> > >>>> > >>>> Hi Frieder, > >>>> > >>>> I found this patch to break mipi-dsi display on my board which has: > >>>> - FocalTech FT5406 10pt touch controller (with no interrupt) > >>>> - Powertip PH800480T013-IDF02 compatible panel > >>>> - Toshiba TC358762 compatible DSI to DBI bridge > >>>> - ATTINY based regulator used for backlight controller and panel enable > >>>> > >>>> I enable this via a dt overlay in a pending patch > >>>> imx8mm-venice-gw72xx-0x-rpidsi.dtso [1] which works on 6.4 but not > >>>> 6.5-rc1 which has this patch. > >>>> > >>>> The issue appears as: > >>>> [ 6.110585] samsung-dsim 32e60000.dsi: xfer timed out: 29 06 00 00 > >>>> 64 01 05 00 00 00 > >>>> [ 6.326588] tc358762 32e60000.dsi.0: error initializing bridge (-110) > >>>> > >>>> Instead of > >>>> [ 1.011729] samsung-dsim 32e10000.dsi: supply vddcore not found, > >>>> using dummy regulator > >>>> [ 1.019829] samsung-dsim 32e10000.dsi: supply vddio not found, > >>>> using dummy regulator > >>>> [ 5.649928] samsung-dsim 32e10000.dsi: > >>>> [drm:samsung_dsim_host_attach] Attached tc358762 device > >>>> > >>>> I'm curious what board/panel were you needing this for and do you have > >>>> any ideas why it broke my setup? > >>>> > >>>> I'm also curious what board/panel Alexander tested this with and if > >>>> Adam or Jagan (or others) have tested this with their hardware? > >>> > >>> Sorry for breaking your setup. My test- and use-case is the same as > >>> Alexander's. I have the SN65DSI84 downstream bridge and without this > >>> patch it fails to come up in some cases. > >>> > >>> The failure is probably related to your downstream bridge being > >>> controlled by the DSI itself using command mode. The SN65DSI84 is > >>> instead controlled via I2C. > >>> > >>> Actually we should have tested this with a bridge that uses command mode > >>> before merging, now that I think of it. But I wasn't really aware of > >>> this until now. > >>> > >>> I'll have a closer look at the issue and then will get back to you. In > >>> the meantime if anyone can help analyze the problem or has proposals how > >>> to fix it, please let us know. > >> > >> With my patch samsung_dsim_init() now initializes the DSIM to stop > >> state. When being called from samsung_dsim_atomic_pre_enable() this > >> works as the stop state is cleared later in samsung_dsim_atomic_enable(). > >> > >> When being called from samsung_dsim_host_transfer() to handle transfers > >> before samsung_dsim_atomic_pre_enable() was called, the stop state is > >> never cleared and transfers will fail. > >> > >> This is the case in your setup as tc358762_init() is called in > >> tc358762_pre_enable(). > >> > >> I think that requiring to initialize the DSI host during transfer could > >> be avoided in this case by moving tc358762_init() from > >> tc358762_pre_enable() to tc358762_enable(). > >> > >> But at the same time according to the docs at [1] this seems to be a > >> valid case that we need to support in the DSIM driver: > >> > >> Whilst it is valid to call host_transfer prior to pre_enable or > >> after post_disable, the exact state of the lanes is undefined at > >> this point. The DSI host should initialise the interface, transmit > >> the data, and then disable the interface again. > >> > >> Therefore I would propose to try a fix like in the attachement. If you > >> could test this, that would be great. > >> > >> Thanks > >> Frieder > >> > >> [1] > >> https://docs.kernel.org/gpu/drm-kms-helpers.html#mipi-dsi-bridge-operation > > > > Hi Frieder, > > > > The patch does not resolve the issue. I still get the 'xfer timed out' > > from samsung-dsim but noticing today that this issue doesn't exist in > > linux-next I've found that its resolved by Marek's patch: > > commit 8a4b2fc9c91a ("drm/bridge: tc358762: Split register programming > > from pre-enable to enable") > > Thanks for testing. I didn't notice there already is a patch from Marek > for the tc358762 driver. This is exactly the change that I was > considering above as a fix on the downstream bridge side. > > > > > I'm not clear on how that patch is staged in linux-next. If we can get > > that pulled into 6.5 then it will resolve the breakage. > > Still the documentation says that the DSI host must be able to handle > this and there might be other drivers that are not yet fixed like this > or can't be changed to make DSI transfers only after the host's > pre_enable() was called. > > Therefore I would prefer to fix the DSIM driver and apply this fix to > 6.5-rc instead of backporting the tc358762 patch. I gave it another shot > and maybe you could do one more test with the attached patch and without > the fix in tc358762. > Frieder, This patch doesn't resolve the issue either. Let me know if there is some quick debugging you want to add somewhere. I don't have a lot of time to troubleshoot this week as I'm trying to wrap up some work before a 2-week vacation but it's quick for me to apply patches and do a quick boot test. best regards, Tim
