[PATCH 3/3] drm/bridge/sii8620: fix loops in EDID fetch logic
Maciej Purski
m.purski at samsung.com
Wed Jun 13 13:12:25 UTC 2018
Hi Andrzej,
On 01/15/2018 06:33 PM, Andrzej Hajda wrote:
> Function should constantly check if cable is connected and finish
> in finite time.
>
> Signed-off-by: Andrzej Hajda <a.hajda at samsung.com>
Looks fine to me.
Reviewed-by: Maciej Purski <m.purski at samsung.com>
> ---
> drivers/gpu/drm/bridge/sil-sii8620.c | 31 ++++++++++++++++++++-----------
> 1 file changed, 20 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/sil-sii8620.c b/drivers/gpu/drm/bridge/sil-sii8620.c
> index 7c46847fef18..f65e14836c0e 100644
> --- a/drivers/gpu/drm/bridge/sil-sii8620.c
> +++ b/drivers/gpu/drm/bridge/sil-sii8620.c
> @@ -801,6 +801,7 @@ static void sii8620_burst_rx_all(struct sii8620 *ctx)
> static void sii8620_fetch_edid(struct sii8620 *ctx)
> {
> u8 lm_ddc, ddc_cmd, int3, cbus;
> + unsigned long timeout;
> int fetched, i;
> int edid_len = EDID_LENGTH;
> u8 *edid;
> @@ -850,23 +851,31 @@ static void sii8620_fetch_edid(struct sii8620 *ctx)
> REG_DDC_CMD, ddc_cmd | VAL_DDC_CMD_ENH_DDC_READ_NO_ACK
> );
>
> - do {
> - int3 = sii8620_readb(ctx, REG_INTR3);
> + int3 = 0;
> + timeout = jiffies + msecs_to_jiffies(200);
> + for (;;) {
> cbus = sii8620_readb(ctx, REG_CBUS_STATUS);
> -
> - if (int3 & BIT_DDC_CMD_DONE)
> - break;
> -
> - if (!(cbus & BIT_CBUS_STATUS_CBUS_CONNECTED)) {
> + if (~cbus & BIT_CBUS_STATUS_CBUS_CONNECTED) {
> + kfree(edid);
> + edid = NULL;
> + goto end;
> + }
> + if (int3 & BIT_DDC_CMD_DONE) {
> + if (sii8620_readb(ctx, REG_DDC_DOUT_CNT)
> + >= FETCH_SIZE)
> + break;
> + } else {
> + int3 = sii8620_readb(ctx, REG_INTR3);
> + }
> + if (time_is_before_jiffies(timeout)) {
> + ctx->error = -ETIMEDOUT;
> + dev_err(ctx->dev, "timeout during EDID read\n");
> kfree(edid);
> edid = NULL;
> goto end;
> }
> - } while (1);
> -
> - sii8620_readb(ctx, REG_DDC_STATUS);
> - while (sii8620_readb(ctx, REG_DDC_DOUT_CNT) < FETCH_SIZE)
> usleep_range(10, 20);
> + }
>
> sii8620_read_buf(ctx, REG_DDC_DATA, edid + fetched, FETCH_SIZE);
> if (fetched + FETCH_SIZE == EDID_LENGTH) {
>
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