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![]() If scatter-gather operation is allowed, a large USB request is split into multiple TRBs. For preparing TRBs for sg list, driver iterates over the list and creates TRB for each sg and mark the chain bit to false for the last sg. The current IOMMU driver is clubbing the list of sgs which shares a page boundary into one and giving it to USB driver. With this the number of sgs mapped it not equal to the the number of sgs passed. Because of this USB driver is not marking the chain bit to false since it couldn't iterate to the last sg. This patch addresses this issue by marking the chain bit to false if it is the last mapped sg. At a practical level, this patch resolves USB transfer stalls seen with adb on dwc3 based db845c, pixel3 and other qcom hardware after functionfs gadget added scatter-gather support around v4.20. Credit also to Anurag Kumar Vulisha <anurag.kumar.vulisha@xilinx.com> who implemented a very similar fix to this issue. Cc: Felipe Balbi <balbi@kernel.org> Cc: Yang Fei <fei.yang@intel.com> Cc: Thinh Nguyen <thinhn@synopsys.com> Cc: Tejas Joglekar <tejas.joglekar@synopsys.com> Cc: Andrzej Pietrasiewicz <andrzej.p@collabora.com> Cc: Jack Pham <jackp@codeaurora.org> Cc: Todd Kjos <tkjos@google.com> Cc: Greg KH <gregkh@linuxfoundation.org> Cc: Linux USB List <linux-usb@vger.kernel.org> Cc: stable <stable@vger.kernel.org> #4.20+ Signed-off-by: Pratham Pratap <prathampratap@codeaurora.org> [jstultz: Slight tweak to remove sg_is_last() usage, reworked commit message, minor comment tweak] Signed-off-by: John Stultz <john.stultz@linaro.org> Link: https://lore.kernel.org/r/20200302214443.55783-1-john.stultz@linaro.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
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.. | ||
core.c | ||
core.h | ||
debug.h | ||
debugfs.c | ||
drd.c | ||
dwc3-exynos.c | ||
dwc3-haps.c | ||
dwc3-keystone.c | ||
dwc3-meson-g12a.c | ||
dwc3-of-simple.c | ||
dwc3-omap.c | ||
dwc3-pci.c | ||
dwc3-qcom.c | ||
dwc3-st.c | ||
ep0.c | ||
gadget.c | ||
gadget.h | ||
host.c | ||
io.h | ||
Kconfig | ||
Makefile | ||
trace.c | ||
trace.h | ||
ulpi.c |