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

[Thomas Perrot <thomas.perrot@bootlin.com>]

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Hello,

On Tue, 2025-06-17 at 16:58 +0200, Aleksander Morgado wrote:
> On Tue, Jun 17, 2025 at 11:27 AM Manivannan Sadhasivam
> <mani@kernel.org> 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.

Sorry, I no longer have the modem to test.

Kind regards,
Thomas Perrot

> > 
> > 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@semtech.com>
> > > ---
> > >  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.
> 

-- 
Thomas Perrot, Bootlin
Embedded Linux and kernel engineering
https://bootlin.com


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