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Commit 664c5f18 authored by Ben Collins's avatar Ben Collins Committed by Bernie Thompson
Browse files

udlfb: Add module_param to allow forcing pixel_limit 



Some user scenarios need to prioritize performance over
maxiumum resolution.

Also, some devices may have bad vendor descriptors, and
this allows the user to set a pixel limit that matches
their specific device to avoid blank screens on higher
resolution monitors.

700000 minimum for DL-115, 2360000 maximum for DL-195

Signed-off-by: default avatarBen Collins <bcollins@ubuntu.com>
Signed-off-by: default avatarBernie Thompson <bernie@plugable.com>
parent b49f184b

drivers/video/udlfb.c

+12 −0
Original line number Diff line number Diff line
@@ -72,6 +72,7 @@ MODULE_DEVICE_TABLE(usb, id_table); 
static bool console = 1; /* Allow fbcon to open framebuffer */

static bool fb_defio = 1;  /* Detect mmap writes using page faults */

static bool shadow = 1; /* Optionally disable shadow framebuffer */

static int pixel_limit; /* Optionally force a pixel resolution limit */



/* dlfb keeps a list of urbs for efficient bulk transfers */

static void dlfb_urb_completion(struct urb *urb);
@@ -1616,6 +1617,14 @@ static int dlfb_usb_probe(struct usb_interface *interface, 
		goto error;

	}



	if (pixel_limit) {

		pr_warn("DL chip limit of %d overriden"

			" by module param to %d\n",

			dev->sku_pixel_limit, pixel_limit);

		dev->sku_pixel_limit = pixel_limit;

	}





	if (!dlfb_alloc_urb_list(dev, WRITES_IN_FLIGHT, MAX_TRANSFER)) {

		retval = -ENOMEM;

		pr_err("dlfb_alloc_urb_list failed\n");
@@ -1963,6 +1972,9 @@ MODULE_PARM_DESC(fb_defio, "Page fault detection of mmap writes"); 
module_param(shadow, bool, S_IWUSR | S_IRUSR | S_IWGRP | S_IRGRP);

MODULE_PARM_DESC(shadow, "Shadow vid mem. Disable to save mem but lose perf");



module_param(pixel_limit, int, S_IWUSR | S_IRUSR | S_IWGRP | S_IRGRP);

MODULE_PARM_DESC(pixel_limit, "Force limit on max mode (in x*y pixels)");



MODULE_AUTHOR("Roberto De Ioris <roberto@unbit.it>, "

	      "Jaya Kumar <jayakumar.lkml@gmail.com>, "

	      "Bernie Thompson <bernie@plugable.com>");