From: Zdenek Dohnal <zdohnal@redhat.com>
Date: Tue, 13 Apr 2021 15:47:37 +0200
Subject: backend/usb-libusb.c: Revert enforcing read limits

This commit reverts the change introduced by 2.2.12 [1] - its
implementation caused a regression with Lexmark filters.

[1] https://github.com/apple/cups/commit/35e927f83529cd9b4bc37bcd418c50e307fced35

Origin: upstream, https://github.com/OpenPrinting/cups/pull/174
Bug: https://github.com/OpenPrinting/cups/issues/72
---
 backend/usb-libusb.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/backend/usb-libusb.c b/backend/usb-libusb.c
index fbb0d9d..89b5182 100644
--- a/backend/usb-libusb.c
+++ b/backend/usb-libusb.c
@@ -1721,7 +1721,8 @@ static void *read_thread(void *reference)
     * Make sure this loop executes no more than once every 250 miliseconds...
     */
 
-    if ((g.wait_eof || !g.read_thread_stop))
+    if ((readstatus != LIBUSB_SUCCESS || rbytes == 0) &&
+	 (g.wait_eof || !g.read_thread_stop))
       usleep(250000);
   }
   while (g.wait_eof || !g.read_thread_stop);