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Commit 26efc758 authored by Treehugger Robot's avatar Treehugger Robot Committed by Automerger Merge Worker
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Merge "fastboot: Increase maximum usbfs bulk size for writes to 256KiB" into main am: c0e1b607 

Original change: https://android-review.googlesource.com/c/platform/system/core/+/2961895



Change-Id: Id7e7ca33204aadaba64c9bb870e3df68b33e80c4
Signed-off-by: default avatarAutomerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>
parents e7e3a9ef c0e1b607

fastboot/usb_linux.cpp

+38 −20
Original line number Diff line number Diff line
@@ -83,7 +83,18 @@ using namespace std::chrono_literals; 
// be reliable.

// 256KiB seems to work, but 1MiB bulk transfers lock up my z620 with a 3.13

// kernel.

#define MAX_USBFS_BULK_SIZE (16 * 1024)

// 128KiB was experimentally found to be enough to saturate the bus at

// SuperSpeed+, so we first try double that for writes. If the operation fails

// due to a lack of contiguous regions (or an ancient kernel), try smaller sizes

// until we find one that works (see LinuxUsbTransport::Write). Reads are less

// performance critical so for now just use a known good size.

#define MAX_USBFS_BULK_WRITE_SIZE (256 * 1024)

#define MAX_USBFS_BULK_READ_SIZE (16 * 1024)



// This size should pretty much always work (it's compatible with pre-3.3

// kernels and it's what we used to use historically), so if it doesn't work

// something has gone badly wrong.

#define MIN_USBFS_BULK_WRITE_SIZE (16 * 1024)



struct usb_handle

{
@@ -108,6 +119,7 @@ class LinuxUsbTransport : public UsbTransport { 
  private:

    std::unique_ptr<usb_handle> handle_;

    const uint32_t ms_timeout_;

    size_t max_usbfs_bulk_write_size_ = MAX_USBFS_BULK_WRITE_SIZE;



    DISALLOW_COPY_AND_ASSIGN(LinuxUsbTransport);

};
@@ -415,7 +427,8 @@ ssize_t LinuxUsbTransport::Write(const void* _data, size_t len) 
    }



    auto submit_urb = [&](size_t i) {

        int xfer = (len > MAX_USBFS_BULK_SIZE) ? MAX_USBFS_BULK_SIZE : len;

        while (true) {

            int xfer = (len > max_usbfs_bulk_write_size_) ? max_usbfs_bulk_write_size_ : len;



            urb[i].type = USBDEVFS_URB_TYPE_BULK;

            urb[i].endpoint = handle_->ep_out;
@@ -425,6 +438,10 @@ ssize_t LinuxUsbTransport::Write(const void* _data, size_t len) 


            int n = ioctl(handle_->desc, USBDEVFS_SUBMITURB, &urb[i]);

            if (n != 0) {

                if (errno == ENOMEM && max_usbfs_bulk_write_size_ > MIN_USBFS_BULK_WRITE_SIZE) {

                    max_usbfs_bulk_write_size_ /= 2;

                    continue;

                }

                DBG("ioctl(USBDEVFS_SUBMITURB) failed\n");

                return false;

            }
@@ -435,6 +452,7 @@ ssize_t LinuxUsbTransport::Write(const void* _data, size_t len) 
            data += xfer;



            return true;

        }

    };



    auto reap_urb = [&](size_t i) {
@@ -500,7 +518,7 @@ ssize_t LinuxUsbTransport::Read(void* _data, size_t len) 
    }



    while (len > 0) {

        int xfer = (len > MAX_USBFS_BULK_SIZE) ? MAX_USBFS_BULK_SIZE : len;

        int xfer = (len > MAX_USBFS_BULK_READ_SIZE) ? MAX_USBFS_BULK_READ_SIZE : len;



        bulk.ep = handle_->ep_in;

        bulk.len = xfer;