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Commit 0de8e353 authored by Randy Dunlap's avatar Randy Dunlap Committed by Mauro Carvalho Chehab
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V4L/DVB: dib3000mc: reduce large stack usage 



This patch reduces static stack usage of one of the 2 top offenders
as listed by 'make checkstack':

Building with CONFIG_FRAME_WARN=2048 produces:

drivers/media/dvb/frontends/dib3000mc.c:853: warning: the frame size of 2224 bytes is larger than 2048 bytes

and in 'make checkstack', the stack usage goes from:
0x00000bbd dib3000mc_i2c_enumeration [dib3000mc]:	2232
to unlisted with this patch.

I don't have the hardware that is needed to test this patch.

Signed-off-by: default avatarRandy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Acked-by: default avatarPatrick Boettcher <pboettcher@kernellabs.com>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@redhat.com>
parent 0b42760a

drivers/media/dvb/frontends/dib3000mc.c

+22 −13
Original line number Diff line number Diff line
@@ -814,42 +814,51 @@ EXPORT_SYMBOL(dib3000mc_set_config); 


int dib3000mc_i2c_enumeration(struct i2c_adapter *i2c, int no_of_demods, u8 default_addr, struct dib3000mc_config cfg[])

{

	struct dib3000mc_state st = { .i2c_adap = i2c };

	struct dib3000mc_state *dmcst;

	int k;

	u8 new_addr;



	static u8 DIB3000MC_I2C_ADDRESS[] = {20,22,24,26};



	dmcst = kzalloc(sizeof(struct dib3000mc_state), GFP_KERNEL);

	if (dmcst == NULL)

		return -ENODEV;



	dmcst->i2c_adap = i2c;



	for (k = no_of_demods-1; k >= 0; k--) {

		st.cfg = &cfg[k];

		dmcst->cfg = &cfg[k];



		/* designated i2c address */

		new_addr          = DIB3000MC_I2C_ADDRESS[k];

		st.i2c_addr = new_addr;

		if (dib3000mc_identify(&st) != 0) {

			st.i2c_addr = default_addr;

			if (dib3000mc_identify(&st) != 0) {

		dmcst->i2c_addr = new_addr;

		if (dib3000mc_identify(dmcst) != 0) {

			dmcst->i2c_addr = default_addr;

			if (dib3000mc_identify(dmcst) != 0) {

				dprintk("-E-  DiB3000P/MC #%d: not identified\n", k);

				kfree(dmcst);

				return -ENODEV;

			}

		}



		dib3000mc_set_output_mode(&st, OUTMODE_MPEG2_PAR_CONT_CLK);

		dib3000mc_set_output_mode(dmcst, OUTMODE_MPEG2_PAR_CONT_CLK);



		// set new i2c address and force divstr (Bit 1) to value 0 (Bit 0)

		dib3000mc_write_word(&st, 1024, (new_addr << 3) | 0x1);

		st.i2c_addr = new_addr;

		dib3000mc_write_word(dmcst, 1024, (new_addr << 3) | 0x1);

		dmcst->i2c_addr = new_addr;

	}



	for (k = 0; k < no_of_demods; k++) {

		st.cfg = &cfg[k];

		st.i2c_addr = DIB3000MC_I2C_ADDRESS[k];

		dmcst->cfg = &cfg[k];

		dmcst->i2c_addr = DIB3000MC_I2C_ADDRESS[k];



		dib3000mc_write_word(&st, 1024, st.i2c_addr << 3);

		dib3000mc_write_word(dmcst, 1024, dmcst->i2c_addr << 3);



		/* turn off data output */

		dib3000mc_set_output_mode(&st, OUTMODE_HIGH_Z);

		dib3000mc_set_output_mode(dmcst, OUTMODE_HIGH_Z);

	}



	kfree(dmcst);

	return 0;

}

EXPORT_SYMBOL(dib3000mc_i2c_enumeration);