From: Dinh Nguyen <dingu...@altera.com>
Even though the IP supports Descriptor DMA mode, it does not support SPLIT
transactions in this mode. So the driver, in its currently form, will not
support LS/FS devices when connected to a HS Hub if Descriptor DMA mode is
enabled.
So we should just default to disable descriptor dma mode.
Signed-off-by: Dinh Nguyen <dingu...@altera.com>
Acked-by: Paul Zimmerman <pa...@synopsys.com>
---
v3:
- remove option for a device tree to turn on descriptor dma
v2:
- Reworked patch to disable descriptor dma by default
- Removed unneeded helper variable
- Reword patch commit header
---
drivers/usb/dwc2/platform.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/usb/dwc2/platform.c b/drivers/usb/dwc2/platform.c
index eaba547..a10e7a3 100644
--- a/drivers/usb/dwc2/platform.c
+++ b/drivers/usb/dwc2/platform.c
@@ -134,6 +134,12 @@ static int dwc2_driver_probe(struct platform_device *dev)
/* Default all params to autodetect */
dwc2_set_all_params(&defparams, -1);
params = &defparams;
+
+ /*
+ * Disable descriptor dma mode by default as the HW can support
+ * it, but does not support it for SPLIT transactions.
+ */
+ defparams.dma_desc_enable = 0;
}
hsotg = devm_kzalloc(&dev->dev, sizeof(*hsotg), GFP_KERNEL);
--
1.7.9.5
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