From: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx> [ Upstream commit f0e7e9ed379c012c4d6b09a09b868accc426223c ] As noticed by Dan ([1] an the followup thread) there are multiple issues with the return values for MSM DSI command transmission callback. In the error case it can easily return a positive value when it should have returned a proper error code. This commits attempts to fix these issues both in TX and in RX paths. [1]: https://lore.kernel.org/linux-arm-msm/20211001123617.GH2283@kili/ Fixes: a689554ba6ed ("drm/msm: Initial add DSI connector support") Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx> Reviewed-by: Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx> Tested-by: Marijn Suijten <marijn.suijten@xxxxxxxxxxxxxx> Patchwork: https://patchwork.freedesktop.org/patch/480501/ Link: https://lore.kernel.org/r/20220401231104.967193-1-dmitry.baryshkov@xxxxxxxxxx Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/gpu/drm/msm/dsi/dsi_host.c | 21 ++++++++++++++------- 1 file changed, 14 insertions(+), 7 deletions(-) diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c index 9abfb19ea7ed..56cfa0a03fd5 100644 --- a/drivers/gpu/drm/msm/dsi/dsi_host.c +++ b/drivers/gpu/drm/msm/dsi/dsi_host.c @@ -1354,10 +1354,10 @@ static int dsi_cmds2buf_tx(struct msm_dsi_host *msm_host, dsi_get_bpp(msm_host->format) / 8; len = dsi_cmd_dma_add(msm_host, msg); - if (!len) { + if (len < 0) { pr_err("%s: failed to add cmd type = 0x%x\n", __func__, msg->type); - return -EINVAL; + return len; } /* for video mode, do not send cmds more than @@ -1376,10 +1376,14 @@ static int dsi_cmds2buf_tx(struct msm_dsi_host *msm_host, } ret = dsi_cmd_dma_tx(msm_host, len); - if (ret < len) { - pr_err("%s: cmd dma tx failed, type=0x%x, data0=0x%x, len=%d\n", - __func__, msg->type, (*(u8 *)(msg->tx_buf)), len); - return -ECOMM; + if (ret < 0) { + pr_err("%s: cmd dma tx failed, type=0x%x, data0=0x%x, len=%d, ret=%d\n", + __func__, msg->type, (*(u8 *)(msg->tx_buf)), len, ret); + return ret; + } else if (ret < len) { + pr_err("%s: cmd dma tx failed, type=0x%x, data0=0x%x, ret=%d len=%d\n", + __func__, msg->type, (*(u8 *)(msg->tx_buf)), ret, len); + return -EIO; } return len; @@ -2105,9 +2109,12 @@ int msm_dsi_host_cmd_rx(struct mipi_dsi_host *host, } ret = dsi_cmds2buf_tx(msm_host, msg); - if (ret < msg->tx_len) { + if (ret < 0) { pr_err("%s: Read cmd Tx failed, %d\n", __func__, ret); return ret; + } else if (ret < msg->tx_len) { + pr_err("%s: Read cmd Tx failed, too short: %d\n", __func__, ret); + return -ECOMM; } /* -- 2.35.1
