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authorThomas Zimmermann <tzimmermann@suse.de>2025-10-13 09:19:19 +0200
committerThomas Zimmermann <tzimmermann@suse.de>2025-10-13 09:19:19 +0200
commit9b966ae42235a88eaea714be09ff3d698535bdfe (patch)
tree7470df78fb74fdfda1f773feb3822c1c9ab38616 /drivers/usb/mon/mon_bin.c
parent5385871282e5c2831c226d32cf2ce26b45a7b164 (diff)
parent3a8660878839faadb4f1a6dd72c3179c1df56787 (diff)
Merge drm/drm-next into drm-misc-next
Updating drm-misc-next to the state of v6.18-rc1. Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Diffstat (limited to 'drivers/usb/mon/mon_bin.c')
-rw-r--r--drivers/usb/mon/mon_bin.c14
1 files changed, 8 insertions, 6 deletions
diff --git a/drivers/usb/mon/mon_bin.c b/drivers/usb/mon/mon_bin.c
index c93b43f5bc46..e713fc5964b1 100644
--- a/drivers/usb/mon/mon_bin.c
+++ b/drivers/usb/mon/mon_bin.c
@@ -68,18 +68,20 @@
* The magic limit was calculated so that it allows the monitoring
* application to pick data once in two ticks. This way, another application,
* which presumably drives the bus, gets to hog CPU, yet we collect our data.
- * If HZ is 100, a 480 mbit/s bus drives 614 KB every jiffy. USB has an
- * enormous overhead built into the bus protocol, so we need about 1000 KB.
+ *
+ * Originally, for a 480 Mbit/s bus this required a buffer of about 1 MB. For
+ * modern 20 Gbps buses, this value increases to over 50 MB. The maximum
+ * buffer size is set to 64 MiB to accommodate this.
*
* This is still too much for most cases, where we just snoop a few
* descriptor fetches for enumeration. So, the default is a "reasonable"
- * amount for systems with HZ=250 and incomplete bus saturation.
+ * amount for typical, low-throughput use cases.
*
* XXX What about multi-megabyte URBs which take minutes to transfer?
*/
-#define BUFF_MAX CHUNK_ALIGN(1200*1024)
-#define BUFF_DFL CHUNK_ALIGN(300*1024)
-#define BUFF_MIN CHUNK_ALIGN(8*1024)
+#define BUFF_MAX CHUNK_ALIGN(64*1024*1024)
+#define BUFF_DFL CHUNK_ALIGN(300*1024)
+#define BUFF_MIN CHUNK_ALIGN(8*1024)
/*
* The per-event API header (2 per URB).