Hotplug support for several PSX controlers

Since 2.6.9, several PSX controlers in the same time can be supported. However, because of a bug, if not all the PSX controlers are pluged in then nothing works. Typically, you load gamecon with options saying that you have two PSX adapter ports and then you plug and unplug has many controllers has you want. There is a bug which prevent keypress to be detected when not all the controllers connected.

The problem was that when a port didn't have a controler pluged the packet length to receive was read as very big, leading to a kind of buffer overflow. This patch checks the packet length and if it is bigger than the theoritical possible it considers that there is no controller pluged on this port.

It probably works on a vanilla 2.6.10-rc3 but I highly recommand to use the Vojtech's tree which contains an important fix about PSX DDR (cf http://marc.theaimsgroup.com/?l=linux-kernel&m=110118014804716&w=2).

I've heard that Linus wants 2.6.10 ready for Christmas, this patch should definitetly helps ;-)

As I added to the documentation "hot swapping should work (but is not recomended)." This might make it a bit more likely to work, but still "not recomended."

This seems like a reasonable explination when ports float if unconnected. Your patch does almost the right thing. First gc_psx_command should take a data[5] argument, that was a logic error on my part. Second, you compare the calculated length to PSX_LENGTH, which is just saying we read in bytes. It should check <= 6, which is the longest string of packets possible (buttons, buttons, right, right, left, left, see
<http://www.gamesx.com/controldata/psxcont/psxcont.htm>). Changing to compare to 6 makes the patch look good to me.

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It probably works on a vanilla 2.6.10-rc3 but I highly recommand to use the Vojtech's tree which contains an important fix about PSX DDR (cf http://marc.theaimsgroup.com/?l=linux-kernel&m=110118014804716&w=2).

Vojtech already accepted my almost-identical patch when I noticed this in September. See
http://marc.theaimsgroup.com/?l=linux-kernel&m=109571247127456&w=4

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I've heard that Linus wants 2.6.10 ready for Christmas, this patch should definitetly helps ;-)

I'm all for both my previous patch and this one making it into 2.6.10 =)

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This seems like a reasonable explination when ports float if unconnected. Your patch does almost the right thing. First gc_psx_command should take a data[5] argument, that was a logic

error on

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my part. Second, you compare the calculated length to PSX_LENGTH,

which

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is just saying we read in bytes. It should check <= 6, which is the longest string of packets possible (buttons, buttons, right, right, left, left, see
<http://www.gamesx.com/controldata/psxcont/psxcont.htm>). Changing to compare to 6 makes the patch look good to me.

I didn't know about the official spec. So changing PSX_LENGTH to 6 makes everything even more correct, good.

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I've heard that Linus wants 2.6.10 ready for Christmas, this patch should definitetly helps ;-)

I'm all for both my previous patch and this one making it into

2.6.10 =)
Is there anyone in particular to tell about those patches? Or is the normal way that Vojtech inserts the patches in his tree and Linus pulls it when he feels it's stable enough?

Eric Piel wrote:

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Is there anyone in particular to tell about those patches? Or is the normal way that Vojtech inserts the patches in his tree and Linus pulls it when he feels it's stable enough?

From what I see Vojtech accepts them and then Linus eventually pulls
from Vojtech's tree. Here is my modified patch. Please test it to double check it works.

---
From: Eric Piel <[email protected]>

Fixes hotplug support for PSX controllers and some mis-sized arrays.

Signed-off-by Peter Nelson <[email protected]>

---
===== gamecon.c 1.19 vs edited =====

gamecon.c 2004-12-13 20:18:02 -05:00 renamed from drivers/input/joystick/gamecon.c 2004-12-13 20:04:39 -05:00 +1 -0

@@ -228,6 +228,7 @@
 
 #define GC_PSX_DELAY    25        /* 25 usec */
 #define GC_PSX_LENGTH    8        /* talk to the controller in bytes */
+#define GC_PSX_BYTES    6        /* the maximum number of bytes to read 

off the controller */

#define GC_PSX_MOUSE 1 /* Mouse */
#define GC_PSX_NEGCON 2 /* NegCon */

gamecon.c 2004-12-13 20:18:02 -05:00 renamed from drivers/input/joystick/gamecon.c 2004-12-13 20:04:39 -05:00 +0 -1

@@ -241,7 +242,7 @@
 #define GC_PSX_SELECT    0x02        /* Pin 3 */
 
 #define GC_PSX_ID(x)    ((x) >> 4)    /* High nibble is device type */
-#define GC_PSX_LEN(x)    ((x) & 0xf)    /* Low nibble is length in 

words */
+#define GC_PSX_LEN(x) (((x) & 0xf) << 1) /* Low nibble is length
in bytes/2 */

static int gc_psx_delay = GC_PSX_DELAY; module_param_named(psx_delay, gc_psx_delay, uint, 0);

gamecon.c 2004-12-13 20:18:02 -05:00 renamed from drivers/input/joystick/gamecon.c 2004-12-13 20:04:39 -05:00 +2 -2

@@ -259,13 +260,13 @@
 * the psx pad.
 */
 
-static void gc_psx_command(struct gc *gc, int b, unsigned char 
 data[GC_PSX_LENGTH])
+static void gc_psx_command(struct gc *gc, int b, unsigned char data[5])
 {
    int i, j, cmd, read;
    for (i = 0; i < 5; i++)
        data[i] = 0;
 
-    for (i = 0; i < 8; i++, b >>= 1) {
+    for (i = 0; i < GC_PSX_LENGTH; i++, b >>= 1) {
        cmd = (b & 1) ? GC_PSX_COMMAND : 0;
        parport_write_data(gc->pd->port, cmd | GC_PSX_POWER);

        udelay(gc_psx_delay);

gamecon.c 2004-12-13 20:18:02 -05:00 renamed from drivers/input/joystick/gamecon.c 2004-12-13 20:04:39 -05:00 +1 -1

@@ -283,7 +284,7 @@
 * device identifier code.
 */
 
-static void gc_psx_read_packet(struct gc *gc, unsigned char 
 data[5][GC_PSX_LENGTH], unsigned char id[5])
+static void gc_psx_read_packet(struct gc *gc, unsigned char 
 data[5][GC_PSX_BYTES], unsigned char id[5])
 {

    int i, j, max_len = 0;
    unsigned long flags;

gamecon.c 2004-12-13 20:18:02 -05:00 renamed from drivers/input/joystick/gamecon.c 2004-12-13 20:04:39 -05:00 +0 -0

@@ -302,10 +303,11 @@
 
    for (i =0; i < 5; i++)                                /* Find the 

longest pad */

        if((gc_status_bit[i] & (gc->pads[GC_PSX] | gc->pads[GC_DDR]))

gamecon.c 2004-12-13 20:18:02 -05:00 renamed from drivers/input/joystick/gamecon.c 2004-12-13 20:04:39 -05:00 +2 -2

-           && (GC_PSX_LEN(id[i]) > max_len))
+           && (GC_PSX_LEN(id[i]) > max_len)
+           && (GC_PSX_LEN(id[i]) <= GC_PSX_BYTES))
            max_len = GC_PSX_LEN(id[i]);
 
-    for (i = 0; i < max_len * 2; i++) {                        /* Read 

in all the data */
+ for (i = 0; i < max_len; i++) { /* Read
in all the data */

        gc_psx_command(gc, 0, data2);
        for (j = 0; j < 5; j++)
            data[j][i] = data2[j];

gamecon.c 2004-12-13 20:18:02 -05:00 renamed from drivers/input/joystick/gamecon.c 2004-12-13 20:04:39 -05:00 +1 -1

@@ -330,7 +332,7 @@
    struct gc *gc = (void *) private;
    struct input_dev *dev = gc->dev;
    unsigned char data[GC_MAX_LENGTH];
-    unsigned char data_psx[5][GC_PSX_LENGTH];
+    unsigned char data_psx[5][GC_PSX_BYTES];
    int i, j, s;
 
 /*