Hi,
On 25-01-18 15:10, Ville Syrjälä wrote:
On Thu, Jan 25, 2018 at 02:37:26PM +0100, Hans de Goede wrote:
So far models of the Dell Venue 8 Pro, with a panel with MIPI panel
index = 3, one of which has been kindly provided to me by Jan Brummer,
where not working with the i915 driver, giving a black screen on the
first modeset.
The problem with at least these Dells is that their VBT defines a MIPI
ASSERT sequence, but not a DEASSERT sequence. Instead they DEASSERT the
reset in their INIT_OTP sequence, but the deassert must be done before
calling intel_dsi_device_ready(), so that is too late.
Simply doing the INIT_OTP sequence earlier is not enough to fix this,
because the INIT_OTP sequence also sends various MIPI packets to the
panel, which can only happen after calling intel_dsi_device_ready().
This commit fixes this by making mipi_exec_send_packet() call
intel_dsi_device_ready() if not done already, so that we can call the
INIT_OTP sequence earlier on affected devices.
Note that this only changes the init-sequence on devices for which
intel_dsi_use_init_otp_as_deassert() returns true, on other devices
intel_dsi->device_ready will be set to true before calling any
MIPI sequences which may send packets, so the check added to
mipi_exec_send_packet() is a nop there.
I don't like how wide this kludge spreads in the code.
Could we instead just extract the deassert sequence from the
OTP sequence? Looks like your code already assumes that everything
up to the first DSI packet is part of the deassert sequence. So
I imagine it should be pretty easy to split the sequence up at
that same point?
Good idea, I've implemented this it results in slightly more code,
but is a lot cleaner indeed.
v2 with this new approach is coming up...
Regards,
Hans
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