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staging: gpib: Fix erroneous removal of blank before newline

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The USB_GPIB_SET_LINES command string used to be: "\nIBDC \n" but when
we were merging this code into the upstream kernel we deleted the space
character before the newline to make checkpatch happy.  That turned
out to be a mistake.

The "\nIBDC" part of the string is a command that we pass to the
firmware and the next character is a variable u8 value.
It gets set in set_control_line().

 msg[leng - 2] = value ? (retval & ~line) : retval | line;

where leng is the length of the command string.

Imagine the parameter was supposed to be "8".
With the pre-merge code the command string would be "\nIBDC8\n"
With the post-merge code the command string became "\nIBD8\n"

The firmware doesn't recognize "IBD8" as a valid command and rejects it.

Putting a "." where the parameter is supposed to go fixes the driver
and makes checkpatch happy.  Same thing with the other define and
the in-line assignment.

Reported-by: Marcello Carla' <marcello.carla@gmx.com>
Fixes: fce79512a9 ("staging: gpib: Add LPVO DIY USB GPIB driver")
Co-developed-by: Marcello Carla' <marcello.carla@gmx.com>
Signed-off-by: Marcello Carla' <marcello.carla@gmx.com>
Signed-off-by: Dave Penkler <dpenkler@gmail.com>
Reviewed-by: Dan Carpenter <dan.carpenter@linaro.org>
Link: https://lore.kernel.org/r/20241205093442.5796-1-dpenkler@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Dave Penkler
2024-12-05 10:34:42 +01:00
committed by Greg Kroah-Hartman
parent 78d4f34e21
commit 4da38536e2
1 changed files with 3 additions and 3 deletions
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6
drivers/staging/gpib/lpvo_usb_gpib/lpvo_usb_gpib.c
View File

@@ -99,8 +99,8 @@ module_param(debug, int, 0644);
#define USB_GPIB_DEBUG_ON "\nIBDE\xAA\n"
#define USB_GPIB_SET_LISTEN "\nIBDT0\n"
#define USB_GPIB_SET_TALK "\nIBDT1\n"
#define USB_GPIB_SET_LINES "\nIBDC\n"
#define USB_GPIB_SET_DATA "\nIBDM\n"
#define USB_GPIB_SET_LINES "\nIBDC.\n"
#define USB_GPIB_SET_DATA "\nIBDM.\n"
#define USB_GPIB_READ_LINES "\nIBD?C\n"
#define USB_GPIB_READ_DATA "\nIBD?M\n"
#define USB_GPIB_READ_BUS "\nIBD??\n"
@@ -589,7 +589,7 @@ static int usb_gpib_command(gpib_board_t *board,
size_t *bytes_written)
{
int i, retval;
char command[6] = "IBc\n";
char command[6] = "IBc.\n";
DIA_LOG(1, "enter %p\n", board);