Re: [PATCH v1] bus: mhi: host: pci_generic: Add support for EM929x and set MRU to 32768 for better performance.

From: Aleksander Morgado
Date: Tue Jun 17 2025 - 10:58:56 EST


On Tue, Jun 17, 2025 at 11:27 AM Manivannan Sadhasivam <mani@xxxxxxxxxx> wrote:
>
> On Wed, May 28, 2025 at 10:59:43AM -0700, Adam Xue wrote:
>
> + Thomas and Aleksander (for EM919X related question)
>
> > Add MHI controller config for EM929x. It uses the same configuration
> > as EM919x. Also set the MRU to 32768 to improve downlink throughput.
> >
>
> This also affects the EM919X modem. So I want either Thomas or Aleksander to
> confirm that it doesn't cause any regression.
>
> Rest looks good to me.
>
> - Mani
>
> > 02:00.0 Unassigned class [ff00]: Qualcomm Technologies, Inc Device 0308
> > Subsystem: Device 18d7:0301
> >
> > Signed-off-by: Adam Xue <zxue@xxxxxxxxxxx>
> > ---
> > drivers/bus/mhi/host/pci_generic.c | 4 ++++
> > 1 file changed, 4 insertions(+)
> >
> > diff --git a/drivers/bus/mhi/host/pci_generic.c b/drivers/bus/mhi/host/pci_generic.c
> > index 03aa88795209..9bf8e7991745 100644
> > --- a/drivers/bus/mhi/host/pci_generic.c
> > +++ b/drivers/bus/mhi/host/pci_generic.c
> > @@ -695,6 +695,7 @@ static const struct mhi_pci_dev_info mhi_sierra_em919x_info = {
> > .config = &modem_sierra_em919x_config,
> > .bar_num = MHI_PCI_DEFAULT_BAR_NUM,
> > .dma_data_width = 32,
> > + .mru_default = 32768,

I cannot test this now, I need to look for the EM9191 that I know I
have somewhere, but this default MRU update feels right. Hopefully
Thomas can verify.