On Fri 31 Aug 13:41 PDT 2018, Frank Rowand wrote:

On 08/30/18 21:07, Bjorn Andersson wrote:

quoted

On Thu 30 Aug 20:57 PDT 2018, Frank Rowand wrote:

quoted

Hi Bjorn,


On 04/19/18 18:17, Bjorn Andersson wrote:

quoted

Attempt to acquire the APCS IPC through the mailbox framework and fall
back to the old syscon based approach, to allow us to move away from
using the syscon.

Reviewed-by: Arun Kumar Neelakantam <redacted>
Signed-off-by: Bjorn Andersson <redacted>
---

Changes since v2:
- Added comment about mbox_send_message() return value.

 .../devicetree/bindings/soc/qcom/qcom,smd.txt      |  8 ++-
 drivers/rpmsg/Kconfig                              |  1 +
 drivers/rpmsg/qcom_smd.c                           | 67 ++++++++++++++++------
 3 files changed, 56 insertions(+), 20 deletions(-)

This patch in the mainline Linux kernel as commit ab460a2e72dabecfdabd45eb7e3ee2d73fc876d4
causes a problem with the APQ8074 Dragonboard.  The mmc device is not set up
with the patch applied, thus I do not have the block device my root file system
is located on.

Testing on v4.18, if I revert this commit the mmc device is available.

I'll reply to this email with the console messages for 4.18 and for 4.18 with
this commit reverted.

The mmc device would fail to come up if the regulators didn't come up,
which would be the result of smd not working. But it should fallback to
the old mechanism if no mailbox is specified.

Can you double check that CONFIG_RPMSG_QCOM_SMD is still set in your
.config after applying and building with this commit included? And if
not, try to enable CONFIG_MAILBOX.

Thank you!

That is indeed the cause.  ab460a2e72da added a "depends on MAILBOX" to
CONFIG_RPMSG_QCOM_SMD, so CONFIG_RPMSG_QCOM_SMD becomes unset since
CONFIG_MAILBOX is not enabled in qcom_defconfig and is not otherwise
selected for the dragonboard.

Thanks for verifying this!

Is there a config variable that should be selecting MAILBOX for a class
of systems that would include the APQ8074 Dragonboard?  For my testing
I added the "select MAILBOX" to CONFIG_ARCH_MSM8974, but I do not know
what systems that includes, and whether it is appropriate to do the
select for all of them.

We typically don't use the CONFIG_ARCH_* to enable user selectable
config options, even if they serve a critical role in the system.

So minimum change would be to add CONFIG_MAILBOX to the qcom_defconfig
(and multi_v7_defconfig I presume). The fuller solution would be to add
qcom,msm8974-apcs-kpss-global (.data is 8) to the qcom-apcs-ipc-mailbox
list of compatibles and replace the syscon currently used, and then
enable these in the defconfigs.

Regards,
Bjorn