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Commit 947ea398 authored by Veera Sundaram Sankaran's avatar Veera Sundaram Sankaran
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msm: mdss: fix req availability check in dsi command commit 



NULL check for req in dsi cmd list commit is misplaced, causing
race condition due to skipping of dsi cmd mdp busy check. This would
eventually result in underflow due to possible contention of using dsi
link. Fix the NULL check to avoid misbehavior.

Change-Id: I5999646d4db67efd0854b3db07e1d987e66c9cb5
Signed-off-by: default avatarVeera Sundaram Sankaran <veeras@codeaurora.org>
parent 729ef8ff

drivers/video/msm/mdss/mdss_dsi_host.c

+7 −4
Original line number Diff line number Diff line
@@ -2059,6 +2059,7 @@ int mdss_dsi_cmdlist_commit(struct mdss_dsi_ctrl_pdata *ctrl, int from_mdp) 
	struct mdss_rect *roi = NULL;

	int ret = -EINVAL;

	int rc = 0;

	bool hs_req = false;



	if (mdss_get_sd_client_cnt())

		return -EPERM;
@@ -2075,8 +2076,8 @@ int mdss_dsi_cmdlist_commit(struct mdss_dsi_ctrl_pdata *ctrl, int from_mdp) 
	MDSS_XLOG(ctrl->ndx, from_mdp, ctrl->mdp_busy, current->pid,

							XLOG_FUNC_ENTRY);



	if (req == NULL)

		goto need_lock;

	if (req && (req->flags & CMD_REQ_HS_MODE))

		hs_req = true;



	/* make sure dsi_cmd_mdp is idle */

	mdss_dsi_cmd_mdp_busy(ctrl);
@@ -2098,11 +2099,13 @@ int mdss_dsi_cmdlist_commit(struct mdss_dsi_ctrl_pdata *ctrl, int from_mdp) 
		}

	} else {	/* from dcs send */

		if (ctrl->shared_data->cmd_clk_ln_recovery_en &&

				ctrl->panel_mode == DSI_CMD_MODE &&

				(req->flags & CMD_REQ_HS_MODE))

				ctrl->panel_mode == DSI_CMD_MODE && hs_req)

			mdss_dsi_cmd_start_hs_clk_lane(ctrl);

	}



	if (!req)

		goto need_lock;



	MDSS_XLOG(ctrl->ndx, req->flags, req->cmds_cnt, from_mdp, current->pid);



	/*