Re: [PATCH net-next v3 2/3] bus: mhi: host: pci_generic: enumerate IP_CTRL channel for Sierra EM919x/EM929x
From: Loic Poulain <loic.poulain@oss.qualcomm.com>
Date: 2026-08-12 06:35:45
Also in:
linux-arm-msm, lkml
On Fri, Aug 7, 2026 at 11:51 PM Peter Hunt [off-list ref] wrote:
IP_CTRL is a standard Qualcomm MHI control channel (channels 18/19) that carries the host serial control lines (DTR/RTS) to the modem; it is not Sierra-specific. It was not enumerated for any device in pci_generic, so the host had no way to drive those signals. Enumerate it in the Sierra em919x channel config (shared by the EM919x and EM929x) using the control event ring. This is the device the change was tested against; other Qualcomm modem configs that expose IP_CTRL can enable it the same way, since the mhi_wwan_ctrl DTR support that consumes it is device-agnostic and binds purely by channel name. Signed-off-by: Peter Hunt <redacted>
Reviewed-by: Loic Poulain <loic.poulain@oss.qualcomm.com>
quoted hunk ↗ jump to hunk
--- drivers/bus/mhi/host/pci_generic.c | 2 ++ 1 file changed, 2 insertions(+)diff --git a/drivers/bus/mhi/host/pci_generic.c b/drivers/bus/mhi/host/pci_generic.c index 0d0d9c7ffa4b..ba47dd153837 100644 --- a/drivers/bus/mhi/host/pci_generic.c +++ b/drivers/bus/mhi/host/pci_generic.c@@ -728,6 +728,8 @@ static const struct mhi_channel_config mhi_sierra_em919x_channels[] = { MHI_CHANNEL_CONFIG_DL(13, "MBIM", 128, 0), MHI_CHANNEL_CONFIG_UL(14, "QMI", 32, 0), MHI_CHANNEL_CONFIG_DL(15, "QMI", 32, 0), + MHI_CHANNEL_CONFIG_UL(18, "IP_CTRL", 32, 0), + MHI_CHANNEL_CONFIG_DL(19, "IP_CTRL", 32, 0), MHI_CHANNEL_CONFIG_UL(32, "DUN", 32, 0), MHI_CHANNEL_CONFIG_DL(33, "DUN", 32, 0), MHI_CHANNEL_CONFIG_HW_UL(100, "IP_HW0", 512, 1), --2.43.0