Re: [RESENDING RFC PATCH 0/4] Add logic to consolidate TRBs for Synopsys xHC

[Greg KH <greg@kroah.com>]

On Fri, Mar 27, 2020 at 02:22:23PM +0530, Tejas Joglekar wrote:
> The Synopsys xHC has an internal TRB cache of size TRB_CACHE_SIZE for
> each endpoint. The default value for TRB_CACHE_SIZE is 16 for SS and 8
> for HS. The controller loads and updates the TRB cache from the
> transfer ring in system memory whenever the driver issues a start
> transfer or update transfer command.
> 
> For chained TRBs, the Synopsys xHC requires that the total amount of
> bytes for all TRBs loaded in the TRB cache be greater than or equal to
> 1 MPS. Or the chain ends within the TRB cache (with a last TRB).
> 
> If this requirement is not met, the controller will not be able to
> send or receive a packet and it will hang causing a driver timeout and
> error.
> 
> This patch set adds logic to the XHCI driver to detect and prevent this
> from happening along with the quirk to enable this logic for Synopsys
> HAPS platform.
> 
> Based on Mathias's feedback on previous implementation where consolidation
> was done in TRB cache, with this patch series the implementation is done
> during mapping of the URB by consolidating the SG list into a temporary
> buffer if the SG list buffer sizes within TRB_CACHE_SIZE is less than MPS.
> 
> 
> Tejas Joglekar (4):
>   dt-bindings: usb: Add snps,consolidate-sgl & consolidate-sgl
>   usb: xhci: Set quirk for XHCI_CONSOLIDATE_SG_LIST
>   usb: dwc3: Add device property consolidate-sgl
>   usb: xhci: Use temporary buffer to consolidate SG
> 
> Resending as 'umlaut' is not accepted by some servers in email.

Only patch 4/4 seems to have gone through :(