Il 26/09/24 09:47, Hermes Wu ha scritto:
From: Hermes Wu <Hermes.wu@xxxxxxxxxx>
The EDID read operation can reach the maximum size of the AUX FIFO buffer.
Fixes: b5c84a9edcd4 ("drm/bridge: add it6505 driver")
Signed-off-by: Hermes Wu <Hermes.wu@xxxxxxxxxx>
---
drivers/gpu/drm/bridge/ite-it6505.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/bridge/ite-it6505.c b/drivers/gpu/drm/bridge/ite-it6505.c
index 28a8043229d3..b451d3c2ac1d 100644
--- a/drivers/gpu/drm/bridge/ite-it6505.c
+++ b/drivers/gpu/drm/bridge/ite-it6505.c
@@ -1078,8 +1078,11 @@ static ssize_t it6505_aux_do_transfer(struct it6505 *it6505,
int i, ret_size, ret = 0, request_size;
int fifo_max_sz = (cmd == CMD_AUX_I2C_EDID_READ) ?
AUX_FIFO_MAX_SIZE : 4;
which later becomes
int fifo_max_sz = (cmd == CMD_AUX_I2C_EDID_READ || cmd == CMD_AUX_GET_KSV_LIST) ?
AUX_FIFO_MAX_SIZE : 4;
otherwise you can do it "the long way"...
if (cmd == .....)
fifo_max_sz = AUX_FIFO_MAX_SIZE;
else
fifo_max_sz = 4;
The point is, cmd won't change during iterations, so it's useless to put that if
branch inside of that loop below.
mutex_lock(&it6505->aux_lock);
- for (i = 0; i < size; i += 4) {
- request_size = min((int)size - i, 4);
request_size = min_t(int, (int)size - i, fifo_max_sz);
P.S.: Also, I'd consider changing this to a do-while instead...
Cheers,
Angelo
+ for (i = 0; i < size; ) {
+ if (cmd == CMD_AUX_I2C_EDID_READ)
+ request_size = min_t(int, (int)size - i, AUX_FIFO_MAX_SIZE);
+ else
+ request_size = min_t(int, (int)size - i, 4);
ret_size = it6505_aux_operation(it6505, cmd, address + i,
buffer + i, request_size,
reply);
@@ -1088,6 +1091,7 @@ static ssize_t it6505_aux_do_transfer(struct it6505 *it6505,
goto aux_op_err;
}
+ i += request_size;
ret += ret_size;
}
